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22 .\" Copyright (c) 2009 Sun Microsystems, Inc. All Rights Reserved.
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32 .Dd Feb 10, 2018
33 .Dt ZFS 1M
34 .Os
35 .Sh NAME
36 .Nm zfs
37 .Nd configures ZFS file systems
38 .Sh SYNOPSIS
39 .Nm
40 .Op Fl \?
41 .Nm
42 .Cm create
43 .Op Fl p
44 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
45 .Ar filesystem
46 .Nm
47 .Cm create
48 .Op Fl ps
49 .Op Fl b Ar blocksize
50 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
51 .Fl V Ar size Ar volume
52 .Nm
53 .Cm destroy
54 .Op Fl Rfnprv
55 .Ar filesystem Ns | Ns Ar volume
56 .Nm
57 .Cm destroy
58 .Op Fl Rdnprv
59 .Ar filesystem Ns | Ns Ar volume Ns @ Ns Ar snap Ns
60 .Oo % Ns Ar snap Ns Oo , Ns Ar snap Ns Oo % Ns Ar snap Oc Oc Oc Ns ...
61 .Nm
62 .Cm destroy
63 .Ar filesystem Ns | Ns Ar volume Ns # Ns Ar bookmark
64 .Nm
65 .Cm snapshot
66 .Op Fl r
67 .Oo Fl o Ar property Ns = Ns value Oc Ns ...
68 .Ar filesystem Ns @ Ns Ar snapname Ns | Ns Ar volume Ns @ Ns Ar snapname Ns ...
69 .Nm
70 .Cm rollback
71 .Op Fl Rfr
72 .Ar snapshot
73 .Nm
74 .Cm clone
75 .Op Fl p
76 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
77 .Ar snapshot Ar filesystem Ns | Ns Ar volume
78 .Nm
79 .Cm promote
80 .Ar clone-filesystem
81 .Nm
82 .Cm rename
83 .Op Fl f
84 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
85 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
86 .Nm
87 .Cm rename
88 .Op Fl fp
89 .Ar filesystem Ns | Ns Ar volume
90 .Ar filesystem Ns | Ns Ar volume
91 .Nm
92 .Cm rename
93 .Fl r
94 .Ar snapshot Ar snapshot
95 .Nm
96 .Cm list
97 .Op Fl r Ns | Ns Fl d Ar depth
98 .Op Fl Hp
99 .Oo Fl o Ar property Ns Oo , Ns Ar property Oc Ns ... Oc
100 .Oo Fl s Ar property Oc Ns ...
101 .Oo Fl S Ar property Oc Ns ...
102 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
103 .Oo Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Oc Ns ...
104 .Nm
105 .Cm remap
106 .Ar filesystem Ns | Ns Ar volume
107 .Nm
108 .Cm set
109 .Ar property Ns = Ns Ar value Oo Ar property Ns = Ns Ar value Oc Ns ...
110 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
111 .Nm
112 .Cm get
113 .Op Fl r Ns | Ns Fl d Ar depth
114 .Op Fl Hp
115 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
116 .Oo Fl s Ar source Ns Oo , Ns Ar source Oc Ns ... Oc
117 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
118 .Cm all | Ar property Ns Oo , Ns Ar property Oc Ns ...
119 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns | Ns Ar bookmark Ns ...
120 .Nm
121 .Cm inherit
122 .Op Fl rS
123 .Ar property Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
124 .Nm
125 .Cm upgrade
126 .Nm
127 .Cm upgrade
128 .Fl v
129 .Nm
130 .Cm upgrade
131 .Op Fl r
132 .Op Fl V Ar version
133 .Fl a | Ar filesystem
134 .Nm
135 .Cm userspace
136 .Op Fl Hinp
137 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
138 .Oo Fl s Ar field Oc Ns ...
139 .Oo Fl S Ar field Oc Ns ...
140 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
141 .Ar filesystem Ns | Ns Ar snapshot
142 .Nm
143 .Cm groupspace
144 .Op Fl Hinp
145 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
146 .Oo Fl s Ar field Oc Ns ...
147 .Oo Fl S Ar field Oc Ns ...
148 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
149 .Ar filesystem Ns | Ns Ar snapshot
150 .Nm
151 .Cm mount
152 .Nm
153 .Cm mount
154 .Op Fl Ov
155 .Op Fl o Ar options
156 .Fl a | Ar filesystem
157 .Nm
158 .Cm unmount
159 .Op Fl f
160 .Fl a | Ar filesystem Ns | Ns Ar mountpoint
161 .Nm
162 .Cm share
163 .Fl a | Ar filesystem
164 .Nm
165 .Cm unshare
166 .Fl a | Ar filesystem Ns | Ns Ar mountpoint
167 .Nm
168 .Cm bookmark
169 .Ar snapshot bookmark
170 .Nm
171 .Cm send
172 .Op Fl DLPRcenpv
173 .Op Oo Fl I Ns | Ns Fl i Oc Ar snapshot
174 .Ar snapshot
175 .Nm
176 .Cm send
177 .Op Fl Lce
178 .Op Fl i Ar snapshot Ns | Ns Ar bookmark
179 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
180 .Nm
181 .Cm send
182 .Op Fl Penv
183 .Fl t Ar receive_resume_token
184 .Nm
185 .Cm receive
186 .Op Fl Fnsuv
187 .Op Fl o Sy origin Ns = Ns Ar snapshot
188 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
189 .Nm
190 .Cm receive
191 .Op Fl Fnsuv
192 .Op Fl d Ns | Ns Fl e
193 .Op Fl o Sy origin Ns = Ns Ar snapshot
194 .Ar filesystem
195 .Nm
196 .Cm receive
197 .Fl A
198 .Ar filesystem Ns | Ns Ar volume
199 .Nm
200 .Cm allow
201 .Ar filesystem Ns | Ns Ar volume
202 .Nm
203 .Cm allow
204 .Op Fl dglu
205 .Ar user Ns | Ns Ar group Ns Oo , Ns Ar user Ns | Ns Ar group Oc Ns ...
206 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
207 .Ar setname Oc Ns ...
208 .Ar filesystem Ns | Ns Ar volume
209 .Nm
210 .Cm allow
211 .Op Fl dl
212 .Fl e Ns | Ns Sy everyone
213 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
214 .Ar setname Oc Ns ...
215 .Ar filesystem Ns | Ns Ar volume
216 .Nm
217 .Cm allow
218 .Fl c
219 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
220 .Ar setname Oc Ns ...
221 .Ar filesystem Ns | Ns Ar volume
222 .Nm
223 .Cm allow
224 .Fl s No @ Ns Ar setname
225 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
226 .Ar setname Oc Ns ...
227 .Ar filesystem Ns | Ns Ar volume
228 .Nm
229 .Cm unallow
230 .Op Fl dglru
231 .Ar user Ns | Ns Ar group Ns Oo , Ns Ar user Ns | Ns Ar group Oc Ns ...
232 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
233 .Ar setname Oc Ns ... Oc
234 .Ar filesystem Ns | Ns Ar volume
235 .Nm
236 .Cm unallow
237 .Op Fl dlr
238 .Fl e Ns | Ns Sy everyone
239 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
240 .Ar setname Oc Ns ... Oc
241 .Ar filesystem Ns | Ns Ar volume
242 .Nm
243 .Cm unallow
244 .Op Fl r
245 .Fl c
246 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
247 .Ar setname Oc Ns ... Oc
248 .Ar filesystem Ns | Ns Ar volume
249 .Nm
250 .Cm unallow
251 .Op Fl r
252 .Fl s @ Ns Ar setname
253 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
254 .Ar setname Oc Ns ... Oc
255 .Ar filesystem Ns | Ns Ar volume
256 .Nm
257 .Cm hold
258 .Op Fl r
259 .Ar tag Ar snapshot Ns ...
260 .Nm
261 .Cm holds
262 .Op Fl r
263 .Ar snapshot Ns ...
264 .Nm
265 .Cm release
266 .Op Fl r
267 .Ar tag Ar snapshot Ns ...
268 .Nm
269 .Cm diff
270 .Op Fl FHt
271 .Ar snapshot Ar snapshot Ns | Ns Ar filesystem
272 .Nm
273 .Cm program
274 .Op Fl n
275 .Op Fl t Ar timeout
276 .Op Fl m Ar memory_limit
277 .Ar pool script
278 .Op Ar arg1 No ...
279 .Sh DESCRIPTION
280 The
281 .Nm
282 command configures ZFS datasets within a ZFS storage pool, as described in
283 .Xr zpool 1M .
284 A dataset is identified by a unique path within the ZFS namespace.
285 For example:
286 .Bd -literal
287 pool/{filesystem,volume,snapshot}
288 .Ed
289 .Pp
290 where the maximum length of a dataset name is
291 .Dv MAXNAMELEN
292 .Pq 256 bytes
293 and the maximum amount of nesting allowed in a path is 50 levels deep.
294 .Pp
295 A dataset can be one of the following:
296 .Bl -tag -width "file system"
297 .It Sy file system
298 A ZFS dataset of type
299 .Sy filesystem
300 can be mounted within the standard system namespace and behaves like other file
301 systems.
302 While ZFS file systems are designed to be POSIX compliant, known issues exist
303 that prevent compliance in some cases.
304 Applications that depend on standards conformance might fail due to non-standard
305 behavior when checking file system free space.
306 .It Sy volume
307 A logical volume exported as a raw or block device.
308 This type of dataset should only be used under special circumstances.
309 File systems are typically used in most environments.
310 .It Sy snapshot
311 A read-only version of a file system or volume at a given point in time.
312 It is specified as
313 .Ar filesystem Ns @ Ns Ar name
314 or
315 .Ar volume Ns @ Ns Ar name .
316 .El
317 .Ss ZFS File System Hierarchy
318 A ZFS storage pool is a logical collection of devices that provide space for
319 datasets.
320 A storage pool is also the root of the ZFS file system hierarchy.
321 .Pp
322 The root of the pool can be accessed as a file system, such as mounting and
323 unmounting, taking snapshots, and setting properties.
324 The physical storage characteristics, however, are managed by the
325 .Xr zpool 1M
326 command.
327 .Pp
328 See
329 .Xr zpool 1M
330 for more information on creating and administering pools.
331 .Ss Snapshots
332 A snapshot is a read-only copy of a file system or volume.
333 Snapshots can be created extremely quickly, and initially consume no additional
334 space within the pool.
335 As data within the active dataset changes, the snapshot consumes more data than
336 would otherwise be shared with the active dataset.
337 .Pp
338 Snapshots can have arbitrary names.
339 Snapshots of volumes can be cloned or rolled back, but cannot be accessed
340 independently.
341 .Pp
342 File system snapshots can be accessed under the
343 .Pa .zfs/snapshot
344 directory in the root of the file system.
345 Snapshots are automatically mounted on demand and may be unmounted at regular
346 intervals.
347 The visibility of the
348 .Pa .zfs
349 directory can be controlled by the
350 .Sy snapdir
351 property.
352 .Ss Clones
353 A clone is a writable volume or file system whose initial contents are the same
354 as another dataset.
355 As with snapshots, creating a clone is nearly instantaneous, and initially
356 consumes no additional space.
357 .Pp
358 Clones can only be created from a snapshot.
359 When a snapshot is cloned, it creates an implicit dependency between the parent
360 and child.
361 Even though the clone is created somewhere else in the dataset hierarchy, the
362 original snapshot cannot be destroyed as long as a clone exists.
363 The
364 .Sy origin
365 property exposes this dependency, and the
366 .Cm destroy
367 command lists any such dependencies, if they exist.
368 .Pp
369 The clone parent-child dependency relationship can be reversed by using the
370 .Cm promote
371 subcommand.
372 This causes the
373 .Qq origin
374 file system to become a clone of the specified file system, which makes it
375 possible to destroy the file system that the clone was created from.
376 .Ss "Mount Points"
377 Creating a ZFS file system is a simple operation, so the number of file systems
378 per system is likely to be numerous.
379 To cope with this, ZFS automatically manages mounting and unmounting file
380 systems without the need to edit the
381 .Pa /etc/vfstab
382 file.
383 All automatically managed file systems are mounted by ZFS at boot time.
384 .Pp
385 By default, file systems are mounted under
386 .Pa /path ,
387 where
388 .Ar path
389 is the name of the file system in the ZFS namespace.
390 Directories are created and destroyed as needed.
391 .Pp
392 A file system can also have a mount point set in the
393 .Sy mountpoint
394 property.
395 This directory is created as needed, and ZFS automatically mounts the file
396 system when the
397 .Nm zfs Cm mount Fl a
398 command is invoked
399 .Po without editing
400 .Pa /etc/vfstab
401 .Pc .
402 The
403 .Sy mountpoint
404 property can be inherited, so if
405 .Em pool/home
406 has a mount point of
407 .Pa /export/stuff ,
408 then
409 .Em pool/home/user
410 automatically inherits a mount point of
411 .Pa /export/stuff/user .
412 .Pp
413 A file system
414 .Sy mountpoint
415 property of
416 .Sy none
417 prevents the file system from being mounted.
418 .Pp
419 If needed, ZFS file systems can also be managed with traditional tools
420 .Po
421 .Nm mount ,
422 .Nm umount ,
423 .Pa /etc/vfstab
424 .Pc .
425 If a file system's mount point is set to
426 .Sy legacy ,
427 ZFS makes no attempt to manage the file system, and the administrator is
428 responsible for mounting and unmounting the file system.
429 .Ss "Zones"
430 A ZFS file system can be added to a non-global zone by using the
431 .Nm zonecfg Cm add Sy fs
432 subcommand.
433 A ZFS file system that is added to a non-global zone must have its
434 .Sy mountpoint
435 property set to
436 .Sy legacy .
437 .Pp
438 The physical properties of an added file system are controlled by the global
439 administrator.
440 However, the zone administrator can create, modify, or destroy files within the
441 added file system, depending on how the file system is mounted.
442 .Pp
443 A dataset can also be delegated to a non-global zone by using the
444 .Nm zonecfg Cm add Sy dataset
445 subcommand.
446 You cannot delegate a dataset to one zone and the children of the same dataset
447 to another zone.
448 The zone administrator can change properties of the dataset or any of its
449 children.
450 However, the
451 .Sy quota ,
452 .Sy filesystem_limit
453 and
454 .Sy snapshot_limit
455 properties of the delegated dataset can be modified only by the global
456 administrator.
457 .Pp
458 A ZFS volume can be added as a device to a non-global zone by using the
459 .Nm zonecfg Cm add Sy device
460 subcommand.
461 However, its physical properties can be modified only by the global
462 administrator.
463 .Pp
464 For more information about
465 .Nm zonecfg
466 syntax, see
467 .Xr zonecfg 1M .
468 .Pp
469 After a dataset is delegated to a non-global zone, the
470 .Sy zoned
471 property is automatically set.
472 A zoned file system cannot be mounted in the global zone, since the zone
473 administrator might have to set the mount point to an unacceptable value.
474 .Pp
475 The global administrator can forcibly clear the
476 .Sy zoned
477 property, though this should be done with extreme care.
478 The global administrator should verify that all the mount points are acceptable
479 before clearing the property.
480 .Ss Native Properties
481 Properties are divided into two types, native properties and user-defined
482 .Po or
483 .Qq user
484 .Pc
485 properties.
486 Native properties either export internal statistics or control ZFS behavior.
487 In addition, native properties are either editable or read-only.
488 User properties have no effect on ZFS behavior, but you can use them to annotate
489 datasets in a way that is meaningful in your environment.
490 For more information about user properties, see the
491 .Sx User Properties
492 section, below.
493 .Pp
494 Every dataset has a set of properties that export statistics about the dataset
495 as well as control various behaviors.
496 Properties are inherited from the parent unless overridden by the child.
497 Some properties apply only to certain types of datasets
498 .Pq file systems, volumes, or snapshots .
499 .Pp
500 The values of numeric properties can be specified using human-readable suffixes
501 .Po for example,
502 .Sy k ,
503 .Sy KB ,
504 .Sy M ,
505 .Sy Gb ,
506 and so forth, up to
507 .Sy Z
508 for zettabyte
509 .Pc .
510 The following are all valid
511 .Pq and equal
512 specifications:
513 .Li 1536M, 1.5g, 1.50GB .
514 .Pp
515 The values of non-numeric properties are case sensitive and must be lowercase,
516 except for
517 .Sy mountpoint ,
518 .Sy sharenfs ,
519 and
520 .Sy sharesmb .
521 .Pp
522 The following native properties consist of read-only statistics about the
523 dataset.
524 These properties can be neither set, nor inherited.
525 Native properties apply to all dataset types unless otherwise noted.
526 .Bl -tag -width "usedbyrefreservation"
527 .It Sy available
528 The amount of space available to the dataset and all its children, assuming that
529 there is no other activity in the pool.
530 Because space is shared within a pool, availability can be limited by any number
531 of factors, including physical pool size, quotas, reservations, or other
532 datasets within the pool.
533 .Pp
534 This property can also be referred to by its shortened column name,
535 .Sy avail .
536 .It Sy compressratio
537 For non-snapshots, the compression ratio achieved for the
538 .Sy used
539 space of this dataset, expressed as a multiplier.
540 The
541 .Sy used
542 property includes descendant datasets, and, for clones, does not include the
543 space shared with the origin snapshot.
544 For snapshots, the
545 .Sy compressratio
546 is the same as the
547 .Sy refcompressratio
548 property.
549 Compression can be turned on by running:
550 .Nm zfs Cm set Sy compression Ns = Ns Sy on Ar dataset .
551 The default value is
552 .Sy off .
553 .It Sy createtxg
554 The transaction group (txg) in which the dataset was created.
555 Bookmarks have the same
556 .Sy createtxg
557 as the snapshot they are initially tied to.
558 This property is suitable for ordering a list of snapshots,
559 e.g. for incremental send and receive.
560 .It Sy creation
561 The time this dataset was created.
562 .It Sy clones
563 For snapshots, this property is a comma-separated list of filesystems or volumes
564 which are clones of this snapshot.
565 The clones'
566 .Sy origin
567 property is this snapshot.
568 If the
569 .Sy clones
570 property is not empty, then this snapshot can not be destroyed
571 .Po even with the
572 .Fl r
573 or
574 .Fl f
575 options
576 .Pc .
577 .It Sy defer_destroy
578 This property is
579 .Sy on
580 if the snapshot has been marked for deferred destroy by using the
581 .Nm zfs Cm destroy Fl d
582 command.
583 Otherwise, the property is
584 .Sy off .
585 .It Sy filesystem_count
586 The total number of filesystems and volumes that exist under this location in
587 the dataset tree.
588 This value is only available when a
589 .Sy filesystem_limit
590 has been set somewhere in the tree under which the dataset resides.
591 .It Sy guid
592 The 64 bit GUID of this dataset or bookmark which does not change over its
593 entire lifetime.
594 When a snapshot is sent to another pool, the received snapshot has the same
595 GUID.
596 Thus, the
597 .Sy guid
598 is suitable to identify a snapshot across pools.
599 .It Sy logicalreferenced
600 The amount of space that is
601 .Qq logically
602 accessible by this dataset.
603 See the
604 .Sy referenced
605 property.
606 The logical space ignores the effect of the
607 .Sy compression
608 and
609 .Sy copies
610 properties, giving a quantity closer to the amount of data that applications
611 see.
612 However, it does include space consumed by metadata.
613 .Pp
614 This property can also be referred to by its shortened column name,
615 .Sy lrefer .
616 .It Sy logicalused
617 The amount of space that is
618 .Qq logically
619 consumed by this dataset and all its descendents.
620 See the
621 .Sy used
622 property.
623 The logical space ignores the effect of the
624 .Sy compression
625 and
626 .Sy copies
627 properties, giving a quantity closer to the amount of data that applications
628 see.
629 However, it does include space consumed by metadata.
630 .Pp
631 This property can also be referred to by its shortened column name,
632 .Sy lused .
633 .It Sy mounted
634 For file systems, indicates whether the file system is currently mounted.
635 This property can be either
636 .Sy yes
637 or
638 .Sy no .
639 .It Sy origin
640 For cloned file systems or volumes, the snapshot from which the clone was
641 created.
642 See also the
643 .Sy clones
644 property.
645 .It Sy receive_resume_token
646 For filesystems or volumes which have saved partially-completed state from
647 .Sy zfs receive -s ,
648 this opaque token can be provided to
649 .Sy zfs send -t
650 to resume and complete the
651 .Sy zfs receive .
652 .It Sy referenced
653 The amount of data that is accessible by this dataset, which may or may not be
654 shared with other datasets in the pool.
655 When a snapshot or clone is created, it initially references the same amount of
656 space as the file system or snapshot it was created from, since its contents are
657 identical.
658 .Pp
659 This property can also be referred to by its shortened column name,
660 .Sy refer .
661 .It Sy refcompressratio
662 The compression ratio achieved for the
663 .Sy referenced
664 space of this dataset, expressed as a multiplier.
665 See also the
666 .Sy compressratio
667 property.
668 .It Sy snapshot_count
669 The total number of snapshots that exist under this location in the dataset
670 tree.
671 This value is only available when a
672 .Sy snapshot_limit
673 has been set somewhere in the tree under which the dataset resides.
674 .It Sy type
675 The type of dataset:
676 .Sy filesystem ,
677 .Sy volume ,
678 or
679 .Sy snapshot .
680 .It Sy used
681 The amount of space consumed by this dataset and all its descendents.
682 This is the value that is checked against this dataset's quota and reservation.
683 The space used does not include this dataset's reservation, but does take into
684 account the reservations of any descendent datasets.
685 The amount of space that a dataset consumes from its parent, as well as the
686 amount of space that is freed if this dataset is recursively destroyed, is the
687 greater of its space used and its reservation.
688 .Pp
689 The used space of a snapshot
690 .Po see the
691 .Sx Snapshots
692 section
693 .Pc
694 is space that is referenced exclusively by this snapshot.
695 If this snapshot is destroyed, the amount of
696 .Sy used
697 space will be freed.
698 Space that is shared by multiple snapshots isn't accounted for in this metric.
699 When a snapshot is destroyed, space that was previously shared with this
700 snapshot can become unique to snapshots adjacent to it, thus changing the used
701 space of those snapshots.
702 The used space of the latest snapshot can also be affected by changes in the
703 file system.
704 Note that the
705 .Sy used
706 space of a snapshot is a subset of the
707 .Sy written
708 space of the snapshot.
709 .Pp
710 The amount of space used, available, or referenced does not take into account
711 pending changes.
712 Pending changes are generally accounted for within a few seconds.
713 Committing a change to a disk using
714 .Xr fsync 3C
715 or
716 .Dv O_SYNC
717 does not necessarily guarantee that the space usage information is updated
718 immediately.
719 .It Sy usedby*
720 The
721 .Sy usedby*
722 properties decompose the
723 .Sy used
724 properties into the various reasons that space is used.
725 Specifically,
726 .Sy used No =
727 .Sy usedbychildren No +
728 .Sy usedbydataset No +
729 .Sy usedbyrefreservation No +
730 .Sy usedbysnapshots .
731 These properties are only available for datasets created on
732 .Nm zpool
733 .Qo version 13 Qc
734 pools.
735 .It Sy usedbychildren
736 The amount of space used by children of this dataset, which would be freed if
737 all the dataset's children were destroyed.
738 .It Sy usedbydataset
739 The amount of space used by this dataset itself, which would be freed if the
740 dataset were destroyed
741 .Po after first removing any
742 .Sy refreservation
743 and destroying any necessary snapshots or descendents
744 .Pc .
745 .It Sy usedbyrefreservation
746 The amount of space used by a
747 .Sy refreservation
748 set on this dataset, which would be freed if the
749 .Sy refreservation
750 was removed.
751 .It Sy usedbysnapshots
752 The amount of space consumed by snapshots of this dataset.
753 In particular, it is the amount of space that would be freed if all of this
754 dataset's snapshots were destroyed.
755 Note that this is not simply the sum of the snapshots'
756 .Sy used
757 properties because space can be shared by multiple snapshots.
758 .It Sy userused Ns @ Ns Em user
759 The amount of space consumed by the specified user in this dataset.
760 Space is charged to the owner of each file, as displayed by
761 .Nm ls Fl l .
762 The amount of space charged is displayed by
763 .Nm du
764 and
765 .Nm ls Fl s .
766 See the
767 .Nm zfs Cm userspace
768 subcommand for more information.
769 .Pp
770 Unprivileged users can access only their own space usage.
771 The root user, or a user who has been granted the
772 .Sy userused
773 privilege with
774 .Nm zfs Cm allow ,
775 can access everyone's usage.
776 .Pp
777 The
778 .Sy userused Ns @ Ns Em ...
779 properties are not displayed by
780 .Nm zfs Cm get Sy all .
781 The user's name must be appended after the @ symbol, using one of the following
782 forms:
783 .Bl -bullet -width ""
784 .It
785 .Em POSIX name
786 .Po for example,
787 .Sy joe
788 .Pc
789 .It
790 .Em POSIX numeric ID
791 .Po for example,
792 .Sy 789
793 .Pc
794 .It
795 .Em SID name
796 .Po for example,
797 .Sy joe.smith@mydomain
798 .Pc
799 .It
800 .Em SID numeric ID
801 .Po for example,
802 .Sy S-1-123-456-789
803 .Pc
804 .El
805 .It Sy userrefs
806 This property is set to the number of user holds on this snapshot.
807 User holds are set by using the
808 .Nm zfs Cm hold
809 command.
810 .It Sy groupused Ns @ Ns Em group
811 The amount of space consumed by the specified group in this dataset.
812 Space is charged to the group of each file, as displayed by
813 .Nm ls Fl l .
814 See the
815 .Sy userused Ns @ Ns Em user
816 property for more information.
817 .Pp
818 Unprivileged users can only access their own groups' space usage.
819 The root user, or a user who has been granted the
820 .Sy groupused
821 privilege with
822 .Nm zfs Cm allow ,
823 can access all groups' usage.
824 .It Sy volblocksize
825 For volumes, specifies the block size of the volume.
826 The
827 .Sy blocksize
828 cannot be changed once the volume has been written, so it should be set at
829 volume creation time.
830 The default
831 .Sy blocksize
832 for volumes is 8 Kbytes.
833 Any power of 2 from 512 bytes to 128 Kbytes is valid.
834 .Pp
835 This property can also be referred to by its shortened column name,
836 .Sy volblock .
837 .It Sy written
838 The amount of space
839 .Sy referenced
840 by this dataset, that was written since the previous snapshot
841 .Pq i.e. that is not referenced by the previous snapshot .
842 .It Sy written Ns @ Ns Em snapshot
843 The amount of
844 .Sy referenced
845 space written to this dataset since the specified snapshot.
846 This is the space that is referenced by this dataset but was not referenced by
847 the specified snapshot.
848 .Pp
849 The
850 .Em snapshot
851 may be specified as a short snapshot name
852 .Po just the part after the
853 .Sy @
854 .Pc ,
855 in which case it will be interpreted as a snapshot in the same filesystem as
856 this dataset.
857 The
858 .Em snapshot
859 may be a full snapshot name
860 .Po Em filesystem Ns @ Ns Em snapshot Pc ,
861 which for clones may be a snapshot in the origin's filesystem
862 .Pq or the origin of the origin's filesystem, etc.
863 .El
864 .Pp
865 The following native properties can be used to change the behavior of a ZFS
866 dataset.
867 .Bl -tag -width ""
868 .It Xo
869 .Sy aclinherit Ns = Ns Sy discard Ns | Ns Sy noallow Ns | Ns
870 .Sy restricted Ns | Ns Sy passthrough Ns | Ns Sy passthrough-x
871 .Xc
872 Controls how ACEs are inherited when files and directories are created.
873 .Bl -tag -width "passthrough-x"
874 .It Sy discard
875 does not inherit any ACEs.
876 .It Sy noallow
877 only inherits inheritable ACEs that specify
878 .Qq deny
879 permissions.
880 .It Sy restricted
881 default, removes the
882 .Sy write_acl
883 and
884 .Sy write_owner
885 permissions when the ACE is inherited.
886 .It Sy passthrough
887 inherits all inheritable ACEs without any modifications.
888 .It Sy passthrough-x
889 same meaning as
890 .Sy passthrough ,
891 except that the
892 .Sy owner@ ,
893 .Sy group@ ,
894 and
895 .Sy everyone@
896 ACEs inherit the execute permission only if the file creation mode also requests
897 the execute bit.
898 .El
899 .Pp
900 When the property value is set to
901 .Sy passthrough ,
902 files are created with a mode determined by the inheritable ACEs.
903 If no inheritable ACEs exist that affect the mode, then the mode is set in
904 accordance to the requested mode from the application.
905 .It Xo
906 .Sy aclmode Ns = Ns Sy discard Ns | Ns Sy groupmask Ns | Ns
907 .Sy passthrough Ns | Ns Sy restricted
908 .Xc
909 Controls how an ACL is modified during
910 .Xr chmod 2
911 and how inherited ACEs are modified by the file creation mode.
912 .Bl -tag -width "passthrough"
913 .It Sy discard
914 default, deletes all ACEs except for those representing the mode of the file or
915 directory requested by
916 .Xr chmod 2 .
917 .It Sy groupmask
918 reduces permissions granted by all
919 .Sy ALLOW
920 entries found in the ACL such that they are no greater than the group
921 permissions specified by the mode.
922 .It Sy passthrough
923 indicates that no changes are made to the ACL other than creating or updating
924 the necessary ACEs to represent the new mode of the file or directory.
925 .It Sy restricted
926 causes the
927 .Xr chmod 2
928 operation to return an error when used on any file or directory which has a
929 non-trivial ACL, with entries in addition to those that represent the mode.
930 .El
931 .Pp
932 .Xr chmod 2
933 is required to change the set user ID, set group ID, or sticky bit on a file or
934 directory, as they do not have equivalent ACEs.
935 In order to use
936 .Xr chmod 2
937 on a file or directory with a non-trivial ACL when
938 .Sy aclmode
939 is set to
940 .Sy restricted ,
941 you must first remove all ACEs except for those that represent the current mode.
942 .It Sy atime Ns = Ns Sy on Ns | Ns Sy off
943 Controls whether the access time for files is updated when they are read.
944 Turning this property off avoids producing write traffic when reading files and
945 can result in significant performance gains, though it might confuse mailers
946 and other similar utilities.
947 The default value is
948 .Sy on .
949 .It Sy canmount Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Sy noauto
950 If this property is set to
951 .Sy off ,
952 the file system cannot be mounted, and is ignored by
953 .Nm zfs Cm mount Fl a .
954 Setting this property to
955 .Sy off
956 is similar to setting the
957 .Sy mountpoint
958 property to
959 .Sy none ,
960 except that the dataset still has a normal
961 .Sy mountpoint
962 property, which can be inherited.
963 Setting this property to
964 .Sy off
965 allows datasets to be used solely as a mechanism to inherit properties.
966 One example of setting
967 .Sy canmount Ns = Ns Sy off
968 is to have two datasets with the same
969 .Sy mountpoint ,
970 so that the children of both datasets appear in the same directory, but might
971 have different inherited characteristics.
972 .Pp
973 When set to
974 .Sy noauto ,
975 a dataset can only be mounted and unmounted explicitly.
976 The dataset is not mounted automatically when the dataset is created or
977 imported, nor is it mounted by the
978 .Nm zfs Cm mount Fl a
979 command or unmounted by the
980 .Nm zfs Cm unmount Fl a
981 command.
982 .Pp
983 This property is not inherited.
984 .It Xo
985 .Sy checksum Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Sy fletcher2 Ns | Ns
986 .Sy fletcher4 Ns | Ns Sy sha256 Ns | Ns Sy noparity Ns | Ns
987 .Sy sha512 Ns | Ns Sy skein Ns | Ns Sy edonr
988 .Xc
989 Controls the checksum used to verify data integrity.
990 The default value is
991 .Sy on ,
992 which automatically selects an appropriate algorithm
993 .Po currently,
994 .Sy fletcher4 ,
995 but this may change in future releases
996 .Pc .
997 The value
998 .Sy off
999 disables integrity checking on user data.
1000 The value
1001 .Sy noparity
1002 not only disables integrity but also disables maintaining parity for user data.
1003 This setting is used internally by a dump device residing on a RAID-Z pool and
1004 should not be used by any other dataset.
1005 Disabling checksums is
1006 .Sy NOT
1007 a recommended practice.
1008 .Pp
1009 The
1010 .Sy sha512 ,
1011 .Sy skein ,
1012 and
1013 .Sy edonr
1014 checksum algorithms require enabling the appropriate features on the pool.
1015 Please see
1016 .Xr zpool-features 5
1017 for more information on these algorithms.
1018 .Pp
1019 Changing this property affects only newly-written data.
1020 .It Xo
1021 .Sy compression Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Sy gzip Ns | Ns
1022 .Sy gzip- Ns Em N Ns | Ns Sy lz4 Ns | Ns Sy lzjb Ns | Ns Sy zle
1023 .Xc
1024 Controls the compression algorithm used for this dataset.
1025 .Pp
1026 Setting compression to
1027 .Sy on
1028 indicates that the current default compression algorithm should be used.
1029 The default balances compression and decompression speed, with compression ratio
1030 and is expected to work well on a wide variety of workloads.
1031 Unlike all other settings for this property,
1032 .Sy on
1033 does not select a fixed compression type.
1034 As new compression algorithms are added to ZFS and enabled on a pool, the
1035 default compression algorithm may change.
1036 The current default compression algorithm is either
1037 .Sy lzjb
1038 or, if the
1039 .Sy lz4_compress
1040 feature is enabled,
1041 .Sy lz4 .
1042 .Pp
1043 The
1044 .Sy lz4
1045 compression algorithm is a high-performance replacement for the
1046 .Sy lzjb
1047 algorithm.
1048 It features significantly faster compression and decompression, as well as a
1049 moderately higher compression ratio than
1050 .Sy lzjb ,
1051 but can only be used on pools with the
1052 .Sy lz4_compress
1053 feature set to
1054 .Sy enabled .
1055 See
1056 .Xr zpool-features 5
1057 for details on ZFS feature flags and the
1058 .Sy lz4_compress
1059 feature.
1060 .Pp
1061 The
1062 .Sy lzjb
1063 compression algorithm is optimized for performance while providing decent data
1064 compression.
1065 .Pp
1066 The
1067 .Sy gzip
1068 compression algorithm uses the same compression as the
1069 .Xr gzip 1
1070 command.
1071 You can specify the
1072 .Sy gzip
1073 level by using the value
1074 .Sy gzip- Ns Em N ,
1075 where
1076 .Em N
1077 is an integer from 1
1078 .Pq fastest
1079 to 9
1080 .Pq best compression ratio .
1081 Currently,
1082 .Sy gzip
1083 is equivalent to
1084 .Sy gzip-6
1085 .Po which is also the default for
1086 .Xr gzip 1
1087 .Pc .
1088 .Pp
1089 The
1090 .Sy zle
1091 compression algorithm compresses runs of zeros.
1092 .Pp
1093 This property can also be referred to by its shortened column name
1094 .Sy compress .
1095 Changing this property affects only newly-written data.
1096 .It Sy copies Ns = Ns Sy 1 Ns | Ns Sy 2 Ns | Ns Sy 3
1097 Controls the number of copies of data stored for this dataset.
1098 These copies are in addition to any redundancy provided by the pool, for
1099 example, mirroring or RAID-Z.
1100 The copies are stored on different disks, if possible.
1101 The space used by multiple copies is charged to the associated file and dataset,
1102 changing the
1103 .Sy used
1104 property and counting against quotas and reservations.
1105 .Pp
1106 Changing this property only affects newly-written data.
1107 Therefore, set this property at file system creation time by using the
1108 .Fl o Sy copies Ns = Ns Ar N
1109 option.
1110 .It Sy devices Ns = Ns Sy on Ns | Ns Sy off
1111 Controls whether device nodes can be opened on this file system.
1112 The default value is
1113 .Sy on .
1114 .It Sy exec Ns = Ns Sy on Ns | Ns Sy off
1115 Controls whether processes can be executed from within this file system.
1116 The default value is
1117 .Sy on .
1118 .It Sy filesystem_limit Ns = Ns Em count Ns | Ns Sy none
1119 Limits the number of filesystems and volumes that can exist under this point in
1120 the dataset tree.
1121 The limit is not enforced if the user is allowed to change the limit.
1122 Setting a
1123 .Sy filesystem_limit
1124 to
1125 .Sy on
1126 a descendent of a filesystem that already has a
1127 .Sy filesystem_limit
1128 does not override the ancestor's
1129 .Sy filesystem_limit ,
1130 but rather imposes an additional limit.
1131 This feature must be enabled to be used
1132 .Po see
1133 .Xr zpool-features 5
1134 .Pc .
1135 .It Sy mountpoint Ns = Ns Pa path Ns | Ns Sy none Ns | Ns Sy legacy
1136 Controls the mount point used for this file system.
1137 See the
1138 .Sx Mount Points
1139 section for more information on how this property is used.
1140 .Pp
1141 When the
1142 .Sy mountpoint
1143 property is changed for a file system, the file system and any children that
1144 inherit the mount point are unmounted.
1145 If the new value is
1146 .Sy legacy ,
1147 then they remain unmounted.
1148 Otherwise, they are automatically remounted in the new location if the property
1149 was previously
1150 .Sy legacy
1151 or
1152 .Sy none ,
1153 or if they were mounted before the property was changed.
1154 In addition, any shared file systems are unshared and shared in the new
1155 location.
1156 .It Sy nbmand Ns = Ns Sy on Ns | Ns Sy off
1157 Controls whether the file system should be mounted with
1158 .Sy nbmand
1159 .Pq Non Blocking mandatory locks .
1160 This is used for SMB clients.
1161 Changes to this property only take effect when the file system is umounted and
1162 remounted.
1163 See
1164 .Xr mount 1M
1165 for more information on
1166 .Sy nbmand
1167 mounts.
1168 .It Sy primarycache Ns = Ns Sy all Ns | Ns Sy none Ns | Ns Sy metadata
1169 Controls what is cached in the primary cache
1170 .Pq ARC .
1171 If this property is set to
1172 .Sy all ,
1173 then both user data and metadata is cached.
1174 If this property is set to
1175 .Sy none ,
1176 then neither user data nor metadata is cached.
1177 If this property is set to
1178 .Sy metadata ,
1179 then only metadata is cached.
1180 The default value is
1181 .Sy all .
1182 .It Sy quota Ns = Ns Em size Ns | Ns Sy none
1183 Limits the amount of space a dataset and its descendents can consume.
1184 This property enforces a hard limit on the amount of space used.
1185 This includes all space consumed by descendents, including file systems and
1186 snapshots.
1187 Setting a quota on a descendent of a dataset that already has a quota does not
1188 override the ancestor's quota, but rather imposes an additional limit.
1189 .Pp
1190 Quotas cannot be set on volumes, as the
1191 .Sy volsize
1192 property acts as an implicit quota.
1193 .It Sy snapshot_limit Ns = Ns Em count Ns | Ns Sy none
1194 Limits the number of snapshots that can be created on a dataset and its
1195 descendents.
1196 Setting a
1197 .Sy snapshot_limit
1198 on a descendent of a dataset that already has a
1199 .Sy snapshot_limit
1200 does not override the ancestor's
1201 .Sy snapshot_limit ,
1202 but rather imposes an additional limit.
1203 The limit is not enforced if the user is allowed to change the limit.
1204 For example, this means that recursive snapshots taken from the global zone are
1205 counted against each delegated dataset within a zone.
1206 This feature must be enabled to be used
1207 .Po see
1208 .Xr zpool-features 5
1209 .Pc .
1210 .It Sy userquota@ Ns Em user Ns = Ns Em size Ns | Ns Sy none
1211 Limits the amount of space consumed by the specified user.
1212 User space consumption is identified by the
1213 .Sy userspace@ Ns Em user
1214 property.
1215 .Pp
1216 Enforcement of user quotas may be delayed by several seconds.
1217 This delay means that a user might exceed their quota before the system notices
1218 that they are over quota and begins to refuse additional writes with the
1219 .Er EDQUOT
1220 error message.
1221 See the
1222 .Nm zfs Cm userspace
1223 subcommand for more information.
1224 .Pp
1225 Unprivileged users can only access their own groups' space usage.
1226 The root user, or a user who has been granted the
1227 .Sy userquota
1228 privilege with
1229 .Nm zfs Cm allow ,
1230 can get and set everyone's quota.
1231 .Pp
1232 This property is not available on volumes, on file systems before version 4, or
1233 on pools before version 15.
1234 The
1235 .Sy userquota@ Ns Em ...
1236 properties are not displayed by
1237 .Nm zfs Cm get Sy all .
1238 The user's name must be appended after the
1239 .Sy @
1240 symbol, using one of the following forms:
1241 .Bl -bullet
1242 .It
1243 .Em POSIX name
1244 .Po for example,
1245 .Sy joe
1246 .Pc
1247 .It
1248 .Em POSIX numeric ID
1249 .Po for example,
1250 .Sy 789
1251 .Pc
1252 .It
1253 .Em SID name
1254 .Po for example,
1255 .Sy joe.smith@mydomain
1256 .Pc
1257 .It
1258 .Em SID numeric ID
1259 .Po for example,
1260 .Sy S-1-123-456-789
1261 .Pc
1262 .El
1263 .It Sy groupquota@ Ns Em group Ns = Ns Em size Ns | Ns Sy none
1264 Limits the amount of space consumed by the specified group.
1265 Group space consumption is identified by the
1266 .Sy groupused@ Ns Em group
1267 property.
1268 .Pp
1269 Unprivileged users can access only their own groups' space usage.
1270 The root user, or a user who has been granted the
1271 .Sy groupquota
1272 privilege with
1273 .Nm zfs Cm allow ,
1274 can get and set all groups' quotas.
1275 .It Sy readonly Ns = Ns Sy on Ns | Ns Sy off
1276 Controls whether this dataset can be modified.
1277 The default value is
1278 .Sy off .
1279 .Pp
1280 This property can also be referred to by its shortened column name,
1281 .Sy rdonly .
1282 .It Sy recordsize Ns = Ns Em size
1283 Specifies a suggested block size for files in the file system.
1284 This property is designed solely for use with database workloads that access
1285 files in fixed-size records.
1286 ZFS automatically tunes block sizes according to internal algorithms optimized
1287 for typical access patterns.
1288 .Pp
1289 For databases that create very large files but access them in small random
1290 chunks, these algorithms may be suboptimal.
1291 Specifying a
1292 .Sy recordsize
1293 greater than or equal to the record size of the database can result in
1294 significant performance gains.
1295 Use of this property for general purpose file systems is strongly discouraged,
1296 and may adversely affect performance.
1297 .Pp
1298 The size specified must be a power of two greater than or equal to 512 and less
1299 than or equal to 128 Kbytes.
1300 If the
1301 .Sy large_blocks
1302 feature is enabled on the pool, the size may be up to 1 Mbyte.
1303 See
1304 .Xr zpool-features 5
1305 for details on ZFS feature flags.
1306 .Pp
1307 Changing the file system's
1308 .Sy recordsize
1309 affects only files created afterward; existing files are unaffected.
1310 .Pp
1311 This property can also be referred to by its shortened column name,
1312 .Sy recsize .
1313 .It Sy redundant_metadata Ns = Ns Sy all Ns | Ns Sy most
1314 Controls what types of metadata are stored redundantly.
1315 ZFS stores an extra copy of metadata, so that if a single block is corrupted,
1316 the amount of user data lost is limited.
1317 This extra copy is in addition to any redundancy provided at the pool level
1318 .Pq e.g. by mirroring or RAID-Z ,
1319 and is in addition to an extra copy specified by the
1320 .Sy copies
1321 property
1322 .Pq up to a total of 3 copies .
1323 For example if the pool is mirrored,
1324 .Sy copies Ns = Ns 2 ,
1325 and
1326 .Sy redundant_metadata Ns = Ns Sy most ,
1327 then ZFS stores 6 copies of most metadata, and 4 copies of data and some
1328 metadata.
1329 .Pp
1330 When set to
1331 .Sy all ,
1332 ZFS stores an extra copy of all metadata.
1333 If a single on-disk block is corrupt, at worst a single block of user data
1334 .Po which is
1335 .Sy recordsize
1336 bytes long
1337 .Pc
1338 can be lost.
1339 .Pp
1340 When set to
1341 .Sy most ,
1342 ZFS stores an extra copy of most types of metadata.
1343 This can improve performance of random writes, because less metadata must be
1344 written.
1345 In practice, at worst about 100 blocks
1346 .Po of
1347 .Sy recordsize
1348 bytes each
1349 .Pc
1350 of user data can be lost if a single on-disk block is corrupt.
1351 The exact behavior of which metadata blocks are stored redundantly may change in
1352 future releases.
1353 .Pp
1354 The default value is
1355 .Sy all .
1356 .It Sy refquota Ns = Ns Em size Ns | Ns Sy none
1357 Limits the amount of space a dataset can consume.
1358 This property enforces a hard limit on the amount of space used.
1359 This hard limit does not include space used by descendents, including file
1360 systems and snapshots.
1361 .It Sy refreservation Ns = Ns Em size Ns | Ns Sy none Ns | Ns Sy auto
1362 The minimum amount of space guaranteed to a dataset, not including its
1363 descendents.
1364 When the amount of space used is below this value, the dataset is treated as if
1365 it were taking up the amount of space specified by
1366 .Sy refreservation .
1367 The
1368 .Sy refreservation
1369 reservation is accounted for in the parent datasets' space used, and counts
1370 against the parent datasets' quotas and reservations.
1371 .Pp
1372 If
1373 .Sy refreservation
1374 is set, a snapshot is only allowed if there is enough free pool space outside of
1375 this reservation to accommodate the current number of
1376 .Qq referenced
1377 bytes in the dataset.
1378 .Pp
1379 If
1380 .Sy refreservation
1381 is set to
1382 .Sy auto ,
1383 a volume is thick provisioned
1384 .Po or
1385 .Qq not sparse
1386 .Pc .
1387 .Sy refreservation Ns = Ns Sy auto
1388 is only supported on volumes.
1389 See
1390 .Sy volsize
1391 in the
1392 .Sx Native Properties
1393 section for more information about sparse volumes.
1394 .Pp
1395 This property can also be referred to by its shortened column name,
1396 .Sy refreserv .
1397 .It Sy reservation Ns = Ns Em size Ns | Ns Sy none
1398 The minimum amount of space guaranteed to a dataset and its descendants.
1399 When the amount of space used is below this value, the dataset is treated as if
1400 it were taking up the amount of space specified by its reservation.
1401 Reservations are accounted for in the parent datasets' space used, and count
1402 against the parent datasets' quotas and reservations.
1403 .Pp
1404 This property can also be referred to by its shortened column name,
1405 .Sy reserv .
1406 .It Sy secondarycache Ns = Ns Sy all Ns | Ns Sy none Ns | Ns Sy metadata
1407 Controls what is cached in the secondary cache
1408 .Pq L2ARC .
1409 If this property is set to
1410 .Sy all ,
1411 then both user data and metadata is cached.
1412 If this property is set to
1413 .Sy none ,
1414 then neither user data nor metadata is cached.
1415 If this property is set to
1416 .Sy metadata ,
1417 then only metadata is cached.
1418 The default value is
1419 .Sy all .
1420 .It Sy setuid Ns = Ns Sy on Ns | Ns Sy off
1421 Controls whether the setuid bit is respected for the file system.
1422 The default value is
1423 .Sy on .
1424 .It Sy sharesmb Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Em opts
1425 Controls whether the file system is shared via SMB, and what options are to be
1426 used.
1427 A file system with the
1428 .Sy sharesmb
1429 property set to
1430 .Sy off
1431 is managed through traditional tools such as
1432 .Xr sharemgr 1M .
1433 Otherwise, the file system is automatically shared and unshared with the
1434 .Nm zfs Cm share
1435 and
1436 .Nm zfs Cm unshare
1437 commands.
1438 If the property is set to
1439 .Sy on ,
1440 the
1441 .Xr sharemgr 1M
1442 command is invoked with no options.
1443 Otherwise, the
1444 .Xr sharemgr 1M
1445 command is invoked with options equivalent to the contents of this property.
1446 .Pp
1447 Because SMB shares requires a resource name, a unique resource name is
1448 constructed from the dataset name.
1449 The constructed name is a copy of the dataset name except that the characters in
1450 the dataset name, which would be invalid in the resource name, are replaced with
1451 underscore
1452 .Pq Sy _
1453 characters.
1454 A pseudo property
1455 .Qq name
1456 is also supported that allows you to replace the data set name with a specified
1457 name.
1458 The specified name is then used to replace the prefix dataset in the case of
1459 inheritance.
1460 For example, if the dataset
1461 .Em data/home/john
1462 is set to
1463 .Sy name Ns = Ns Sy john ,
1464 then
1465 .Em data/home/john
1466 has a resource name of
1467 .Sy john .
1468 If a child dataset
1469 .Em data/home/john/backups
1470 is shared, it has a resource name of
1471 .Sy john_backups .
1472 .Pp
1473 When SMB shares are created, the SMB share name appears as an entry in the
1474 .Pa .zfs/shares
1475 directory.
1476 You can use the
1477 .Nm ls
1478 or
1479 .Nm chmod
1480 command to display the share-level ACLs on the entries in this directory.
1481 .Pp
1482 When the
1483 .Sy sharesmb
1484 property is changed for a dataset, the dataset and any children inheriting the
1485 property are re-shared with the new options, only if the property was previously
1486 set to
1487 .Sy off ,
1488 or if they were shared before the property was changed.
1489 If the new property is set to
1490 .Sy off ,
1491 the file systems are unshared.
1492 .It Sy sharenfs Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Em opts
1493 Controls whether the file system is shared via NFS, and what options are to be
1494 used.
1495 A file system with a
1496 .Sy sharenfs
1497 property of
1498 .Sy off
1499 is managed through traditional tools such as
1500 .Xr share 1M ,
1501 .Xr unshare 1M ,
1502 and
1503 .Xr dfstab 4 .
1504 Otherwise, the file system is automatically shared and unshared with the
1505 .Nm zfs Cm share
1506 and
1507 .Nm zfs Cm unshare
1508 commands.
1509 If the property is set to
1510 .Sy on ,
1511 .Xr share 1M
1512 command is invoked with no options.
1513 Otherwise, the
1514 .Xr share 1M
1515 command is invoked with options equivalent to the contents of this property.
1516 .Pp
1517 When the
1518 .Sy sharenfs
1519 property is changed for a dataset, the dataset and any children inheriting the
1520 property are re-shared with the new options, only if the property was previously
1521 .Sy off ,
1522 or if they were shared before the property was changed.
1523 If the new property is
1524 .Sy off ,
1525 the file systems are unshared.
1526 .It Sy logbias Ns = Ns Sy latency Ns | Ns Sy throughput
1527 Provide a hint to ZFS about handling of synchronous requests in this dataset.
1528 If
1529 .Sy logbias
1530 is set to
1531 .Sy latency
1532 .Pq the default ,
1533 ZFS will use pool log devices
1534 .Pq if configured
1535 to handle the requests at low latency.
1536 If
1537 .Sy logbias
1538 is set to
1539 .Sy throughput ,
1540 ZFS will not use configured pool log devices.
1541 ZFS will instead optimize synchronous operations for global pool throughput and
1542 efficient use of resources.
1543 .It Sy snapdir Ns = Ns Sy hidden Ns | Ns Sy visible
1544 Controls whether the
1545 .Pa .zfs
1546 directory is hidden or visible in the root of the file system as discussed in
1547 the
1548 .Sx Snapshots
1549 section.
1550 The default value is
1551 .Sy hidden .
1552 .It Sy sync Ns = Ns Sy standard Ns | Ns Sy always Ns | Ns Sy disabled
1553 Controls the behavior of synchronous requests
1554 .Pq e.g. fsync, O_DSYNC .
1555 .Sy standard
1556 is the
1557 .Tn POSIX
1558 specified behavior of ensuring all synchronous requests are written to stable
1559 storage and all devices are flushed to ensure data is not cached by device
1560 controllers
1561 .Pq this is the default .
1562 .Sy always
1563 causes every file system transaction to be written and flushed before its
1564 system call returns.
1565 This has a large performance penalty.
1566 .Sy disabled
1567 disables synchronous requests.
1568 File system transactions are only committed to stable storage periodically.
1569 This option will give the highest performance.
1570 However, it is very dangerous as ZFS would be ignoring the synchronous
1571 transaction demands of applications such as databases or NFS.
1572 Administrators should only use this option when the risks are understood.
1573 .It Sy version Ns = Ns Em N Ns | Ns Sy current
1574 The on-disk version of this file system, which is independent of the pool
1575 version.
1576 This property can only be set to later supported versions.
1577 See the
1578 .Nm zfs Cm upgrade
1579 command.
1580 .It Sy volsize Ns = Ns Em size
1581 For volumes, specifies the logical size of the volume.
1582 By default, creating a volume establishes a reservation of equal size.
1583 For storage pools with a version number of 9 or higher, a
1584 .Sy refreservation
1585 is set instead.
1586 Any changes to
1587 .Sy volsize
1588 are reflected in an equivalent change to the reservation
1589 .Po or
1590 .Sy refreservation
1591 .Pc .
1592 The
1593 .Sy volsize
1594 can only be set to a multiple of
1595 .Sy volblocksize ,
1596 and cannot be zero.
1597 .Pp
1598 The reservation is kept equal to the volume's logical size to prevent unexpected
1599 behavior for consumers.
1600 Without the reservation, the volume could run out of space, resulting in
1601 undefined behavior or data corruption, depending on how the volume is used.
1602 These effects can also occur when the volume size is changed while it is in use
1603 .Pq particularly when shrinking the size .
1604 Extreme care should be used when adjusting the volume size.
1605 .Pp
1606 Though not recommended, a
1607 .Qq sparse volume
1608 .Po also known as
1609 .Qq thin provisioned
1610 .Pc
1611 can be created by specifying the
1612 .Fl s
1613 option to the
1614 .Nm zfs Cm create Fl V
1615 command, or by changing the value of the
1616 .Sy refreservation
1617 property
1618 .Po or
1619 .Sy reservation
1620 property on pool version 8 or earlier
1621 .Pc
1622 after the volume has been created.
1623 A
1624 .Qq sparse volume
1625 is a volume where the value of
1626 .Sy refreservation
1627 is less than the size of the volume plus the space required to store its
1628 metadata.
1629 Consequently, writes to a sparse volume can fail with
1630 .Er ENOSPC
1631 when the pool is low on space.
1632 For a sparse volume, changes to
1633 .Sy volsize
1634 are not reflected in the
1635 .Sy refreservation.
1636 A volume that is not sparse is said to be
1637 .Qq thick provisioned .
1638 A sparse volume can become thick provisioned by setting
1639 .Sy refreservation
1640 to
1641 .Sy auto .
1642 .It Sy vscan Ns = Ns Sy on Ns | Ns Sy off
1643 Controls whether regular files should be scanned for viruses when a file is
1644 opened and closed.
1645 In addition to enabling this property, the virus scan service must also be
1646 enabled for virus scanning to occur.
1647 The default value is
1648 .Sy off .
1649 .It Sy xattr Ns = Ns Sy on Ns | Ns Sy off
1650 Controls whether extended attributes are enabled for this file system.
1651 The default value is
1652 .Sy on .
1653 .It Sy zoned Ns = Ns Sy on Ns | Ns Sy off
1654 Controls whether the dataset is managed from a non-global zone.
1655 See the
1656 .Sx Zones
1657 section for more information.
1658 The default value is
1659 .Sy off .
1660 .El
1661 .Pp
1662 The following three properties cannot be changed after the file system is
1663 created, and therefore, should be set when the file system is created.
1664 If the properties are not set with the
1665 .Nm zfs Cm create
1666 or
1667 .Nm zpool Cm create
1668 commands, these properties are inherited from the parent dataset.
1669 If the parent dataset lacks these properties due to having been created prior to
1670 these features being supported, the new file system will have the default values
1671 for these properties.
1672 .Bl -tag -width ""
1673 .It Xo
1674 .Sy casesensitivity Ns = Ns Sy sensitive Ns | Ns
1675 .Sy insensitive Ns | Ns Sy mixed
1676 .Xc
1677 Indicates whether the file name matching algorithm used by the file system
1678 should be case-sensitive, case-insensitive, or allow a combination of both
1679 styles of matching.
1680 The default value for the
1681 .Sy casesensitivity
1682 property is
1683 .Sy sensitive .
1684 Traditionally,
1685 .Ux
1686 and
1687 .Tn POSIX
1688 file systems have case-sensitive file names.
1689 .Pp
1690 The
1691 .Sy mixed
1692 value for the
1693 .Sy casesensitivity
1694 property indicates that the file system can support requests for both
1695 case-sensitive and case-insensitive matching behavior.
1696 Currently, case-insensitive matching behavior on a file system that supports
1697 mixed behavior is limited to the SMB server product.
1698 For more information about the
1699 .Sy mixed
1700 value behavior, see the "ZFS Administration Guide".
1701 .It Xo
1702 .Sy normalization Ns = Ns Sy none Ns | Ns Sy formC Ns | Ns
1703 .Sy formD Ns | Ns Sy formKC Ns | Ns Sy formKD
1704 .Xc
1705 Indicates whether the file system should perform a
1706 .Sy unicode
1707 normalization of file names whenever two file names are compared, and which
1708 normalization algorithm should be used.
1709 File names are always stored unmodified, names are normalized as part of any
1710 comparison process.
1711 If this property is set to a legal value other than
1712 .Sy none ,
1713 and the
1714 .Sy utf8only
1715 property was left unspecified, the
1716 .Sy utf8only
1717 property is automatically set to
1718 .Sy on .
1719 The default value of the
1720 .Sy normalization
1721 property is
1722 .Sy none .
1723 This property cannot be changed after the file system is created.
1724 .It Sy utf8only Ns = Ns Sy on Ns | Ns Sy off
1725 Indicates whether the file system should reject file names that include
1726 characters that are not present in the
1727 .Sy UTF-8
1728 character code set.
1729 If this property is explicitly set to
1730 .Sy off ,
1731 the normalization property must either not be explicitly set or be set to
1732 .Sy none .
1733 The default value for the
1734 .Sy utf8only
1735 property is
1736 .Sy off .
1737 This property cannot be changed after the file system is created.
1738 .El
1739 .Pp
1740 The
1741 .Sy casesensitivity ,
1742 .Sy normalization ,
1743 and
1744 .Sy utf8only
1745 properties are also new permissions that can be assigned to non-privileged users
1746 by using the ZFS delegated administration feature.
1747 .Ss "Temporary Mount Point Properties"
1748 When a file system is mounted, either through
1749 .Xr mount 1M
1750 for legacy mounts or the
1751 .Nm zfs Cm mount
1752 command for normal file systems, its mount options are set according to its
1753 properties.
1754 The correlation between properties and mount options is as follows:
1755 .Bd -literal
1756 PROPERTY MOUNT OPTION
1757 devices devices/nodevices
1758 exec exec/noexec
1759 readonly ro/rw
1760 setuid setuid/nosetuid
1761 xattr xattr/noxattr
1762 .Ed
1763 .Pp
1764 In addition, these options can be set on a per-mount basis using the
1765 .Fl o
1766 option, without affecting the property that is stored on disk.
1767 The values specified on the command line override the values stored in the
1768 dataset.
1769 The
1770 .Sy nosuid
1771 option is an alias for
1772 .Sy nodevices Ns \&, Ns Sy nosetuid .
1773 These properties are reported as
1774 .Qq temporary
1775 by the
1776 .Nm zfs Cm get
1777 command.
1778 If the properties are changed while the dataset is mounted, the new setting
1779 overrides any temporary settings.
1780 .Ss "User Properties"
1781 In addition to the standard native properties, ZFS supports arbitrary user
1782 properties.
1783 User properties have no effect on ZFS behavior, but applications or
1784 administrators can use them to annotate datasets
1785 .Pq file systems, volumes, and snapshots .
1786 .Pp
1787 User property names must contain a colon
1788 .Pq Qq Sy \&:
1789 character to distinguish them from native properties.
1790 They may contain lowercase letters, numbers, and the following punctuation
1791 characters: colon
1792 .Pq Qq Sy \&: ,
1793 dash
1794 .Pq Qq Sy - ,
1795 period
1796 .Pq Qq Sy \&. ,
1797 and underscore
1798 .Pq Qq Sy _ .
1799 The expected convention is that the property name is divided into two portions
1800 such as
1801 .Em module Ns \&: Ns Em property ,
1802 but this namespace is not enforced by ZFS.
1803 User property names can be at most 256 characters, and cannot begin with a dash
1804 .Pq Qq Sy - .
1805 .Pp
1806 When making programmatic use of user properties, it is strongly suggested to use
1807 a reversed
1808 .Sy DNS
1809 domain name for the
1810 .Em module
1811 component of property names to reduce the chance that two
1812 independently-developed packages use the same property name for different
1813 purposes.
1814 .Pp
1815 The values of user properties are arbitrary strings, are always inherited, and
1816 are never validated.
1817 All of the commands that operate on properties
1818 .Po Nm zfs Cm list ,
1819 .Nm zfs Cm get ,
1820 .Nm zfs Cm set ,
1821 and so forth
1822 .Pc
1823 can be used to manipulate both native properties and user properties.
1824 Use the
1825 .Nm zfs Cm inherit
1826 command to clear a user property.
1827 If the property is not defined in any parent dataset, it is removed entirely.
1828 Property values are limited to 8192 bytes.
1829 .Ss ZFS Volumes as Swap or Dump Devices
1830 During an initial installation a swap device and dump device are created on ZFS
1831 volumes in the ZFS root pool.
1832 By default, the swap area size is based on 1/2 the size of physical memory up to
1833 2 Gbytes.
1834 The size of the dump device depends on the kernel's requirements at installation
1835 time.
1836 Separate ZFS volumes must be used for the swap area and dump devices.
1837 Do not swap to a file on a ZFS file system.
1838 A ZFS swap file configuration is not supported.
1839 .Pp
1840 If you need to change your swap area or dump device after the system is
1841 installed or upgraded, use the
1842 .Xr swap 1M
1843 and
1844 .Xr dumpadm 1M
1845 commands.
1846 .Sh SUBCOMMANDS
1847 All subcommands that modify state are logged persistently to the pool in their
1848 original form.
1849 .Bl -tag -width ""
1850 .It Nm Fl \?
1851 Displays a help message.
1852 .It Xo
1853 .Nm
1854 .Cm create
1855 .Op Fl p
1856 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
1857 .Ar filesystem
1858 .Xc
1859 Creates a new ZFS file system.
1860 The file system is automatically mounted according to the
1861 .Sy mountpoint
1862 property inherited from the parent.
1863 .Bl -tag -width "-o"
1864 .It Fl o Ar property Ns = Ns Ar value
1865 Sets the specified property as if the command
1866 .Nm zfs Cm set Ar property Ns = Ns Ar value
1867 was invoked at the same time the dataset was created.
1868 Any editable ZFS property can also be set at creation time.
1869 Multiple
1870 .Fl o
1871 options can be specified.
1872 An error results if the same property is specified in multiple
1873 .Fl o
1874 options.
1875 .It Fl p
1876 Creates all the non-existing parent datasets.
1877 Datasets created in this manner are automatically mounted according to the
1878 .Sy mountpoint
1879 property inherited from their parent.
1880 Any property specified on the command line using the
1881 .Fl o
1882 option is ignored.
1883 If the target filesystem already exists, the operation completes successfully.
1884 .El
1885 .It Xo
1886 .Nm
1887 .Cm create
1888 .Op Fl ps
1889 .Op Fl b Ar blocksize
1890 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
1891 .Fl V Ar size Ar volume
1892 .Xc
1893 Creates a volume of the given size.
1894 The volume is exported as a block device in
1895 .Pa /dev/zvol/{dsk,rdsk}/path ,
1896 where
1897 .Em path
1898 is the name of the volume in the ZFS namespace.
1899 The size represents the logical size as exported by the device.
1900 By default, a reservation of equal size is created.
1901 .Pp
1902 .Ar size
1903 is automatically rounded up to the nearest 128 Kbytes to ensure that the volume
1904 has an integral number of blocks regardless of
1905 .Sy blocksize .
1906 .Bl -tag -width "-b"
1907 .It Fl b Ar blocksize
1908 Equivalent to
1909 .Fl o Sy volblocksize Ns = Ns Ar blocksize .
1910 If this option is specified in conjunction with
1911 .Fl o Sy volblocksize ,
1912 the resulting behavior is undefined.
1913 .It Fl o Ar property Ns = Ns Ar value
1914 Sets the specified property as if the
1915 .Nm zfs Cm set Ar property Ns = Ns Ar value
1916 command was invoked at the same time the dataset was created.
1917 Any editable ZFS property can also be set at creation time.
1918 Multiple
1919 .Fl o
1920 options can be specified.
1921 An error results if the same property is specified in multiple
1922 .Fl o
1923 options.
1924 .It Fl p
1925 Creates all the non-existing parent datasets.
1926 Datasets created in this manner are automatically mounted according to the
1927 .Sy mountpoint
1928 property inherited from their parent.
1929 Any property specified on the command line using the
1930 .Fl o
1931 option is ignored.
1932 If the target filesystem already exists, the operation completes successfully.
1933 .It Fl s
1934 Creates a sparse volume with no reservation.
1935 See
1936 .Sy volsize
1937 in the
1938 .Sx Native Properties
1939 section for more information about sparse volumes.
1940 .El
1941 .It Xo
1942 .Nm
1943 .Cm destroy
1944 .Op Fl Rfnprv
1945 .Ar filesystem Ns | Ns Ar volume
1946 .Xc
1947 Destroys the given dataset.
1948 By default, the command unshares any file systems that are currently shared,
1949 unmounts any file systems that are currently mounted, and refuses to destroy a
1950 dataset that has active dependents
1951 .Pq children or clones .
1952 .Bl -tag -width "-R"
1953 .It Fl R
1954 Recursively destroy all dependents, including cloned file systems outside the
1955 target hierarchy.
1956 .It Fl f
1957 Force an unmount of any file systems using the
1958 .Nm unmount Fl f
1959 command.
1960 This option has no effect on non-file systems or unmounted file systems.
1961 .It Fl n
1962 Do a dry-run
1963 .Pq Qq No-op
1964 deletion.
1965 No data will be deleted.
1966 This is useful in conjunction with the
1967 .Fl v
1968 or
1969 .Fl p
1970 flags to determine what data would be deleted.
1971 .It Fl p
1972 Print machine-parsable verbose information about the deleted data.
1973 .It Fl r
1974 Recursively destroy all children.
1975 .It Fl v
1976 Print verbose information about the deleted data.
1977 .El
1978 .Pp
1979 Extreme care should be taken when applying either the
1980 .Fl r
1981 or the
1982 .Fl R
1983 options, as they can destroy large portions of a pool and cause unexpected
1984 behavior for mounted file systems in use.
1985 .It Xo
1986 .Nm
1987 .Cm destroy
1988 .Op Fl Rdnprv
1989 .Ar filesystem Ns | Ns Ar volume Ns @ Ns Ar snap Ns
1990 .Oo % Ns Ar snap Ns Oo , Ns Ar snap Ns Oo % Ns Ar snap Oc Oc Oc Ns ...
1991 .Xc
1992 The given snapshots are destroyed immediately if and only if the
1993 .Nm zfs Cm destroy
1994 command without the
1995 .Fl d
1996 option would have destroyed it.
1997 Such immediate destruction would occur, for example, if the snapshot had no
1998 clones and the user-initiated reference count were zero.
1999 .Pp
2000 If a snapshot does not qualify for immediate destruction, it is marked for
2001 deferred deletion.
2002 In this state, it exists as a usable, visible snapshot until both of the
2003 preconditions listed above are met, at which point it is destroyed.
2004 .Pp
2005 An inclusive range of snapshots may be specified by separating the first and
2006 last snapshots with a percent sign.
2007 The first and/or last snapshots may be left blank, in which case the
2008 filesystem's oldest or newest snapshot will be implied.
2009 .Pp
2010 Multiple snapshots
2011 .Pq or ranges of snapshots
2012 of the same filesystem or volume may be specified in a comma-separated list of
2013 snapshots.
2014 Only the snapshot's short name
2015 .Po the part after the
2016 .Sy @
2017 .Pc
2018 should be specified when using a range or comma-separated list to identify
2019 multiple snapshots.
2020 .Bl -tag -width "-R"
2021 .It Fl R
2022 Recursively destroy all clones of these snapshots, including the clones,
2023 snapshots, and children.
2024 If this flag is specified, the
2025 .Fl d
2026 flag will have no effect.
2027 .It Fl d
2028 Defer snapshot deletion.
2029 .It Fl n
2030 Do a dry-run
2031 .Pq Qq No-op
2032 deletion.
2033 No data will be deleted.
2034 This is useful in conjunction with the
2035 .Fl p
2036 or
2037 .Fl v
2038 flags to determine what data would be deleted.
2039 .It Fl p
2040 Print machine-parsable verbose information about the deleted data.
2041 .It Fl r
2042 Destroy
2043 .Pq or mark for deferred deletion
2044 all snapshots with this name in descendent file systems.
2045 .It Fl v
2046 Print verbose information about the deleted data.
2047 .Pp
2048 Extreme care should be taken when applying either the
2049 .Fl r
2050 or the
2051 .Fl R
2052 options, as they can destroy large portions of a pool and cause unexpected
2053 behavior for mounted file systems in use.
2054 .El
2055 .It Xo
2056 .Nm
2057 .Cm destroy
2058 .Ar filesystem Ns | Ns Ar volume Ns # Ns Ar bookmark
2059 .Xc
2060 The given bookmark is destroyed.
2061 .It Xo
2062 .Nm
2063 .Cm snapshot
2064 .Op Fl r
2065 .Oo Fl o Ar property Ns = Ns value Oc Ns ...
2066 .Ar filesystem Ns @ Ns Ar snapname Ns | Ns Ar volume Ns @ Ns Ar snapname Ns ...
2067 .Xc
2068 Creates snapshots with the given names.
2069 All previous modifications by successful system calls to the file system are
2070 part of the snapshots.
2071 Snapshots are taken atomically, so that all snapshots correspond to the same
2072 moment in time.
2073 See the
2074 .Sx Snapshots
2075 section for details.
2076 .Bl -tag -width "-o"
2077 .It Fl o Ar property Ns = Ns Ar value
2078 Sets the specified property; see
2079 .Nm zfs Cm create
2080 for details.
2081 .It Fl r
2082 Recursively create snapshots of all descendent datasets
2083 .El
2084 .It Xo
2085 .Nm
2086 .Cm rollback
2087 .Op Fl Rfr
2088 .Ar snapshot
2089 .Xc
2090 Roll back the given dataset to a previous snapshot.
2091 When a dataset is rolled back, all data that has changed since the snapshot is
2092 discarded, and the dataset reverts to the state at the time of the snapshot.
2093 By default, the command refuses to roll back to a snapshot other than the most
2094 recent one.
2095 In order to do so, all intermediate snapshots and bookmarks must be destroyed by
2096 specifying the
2097 .Fl r
2098 option.
2099 .Pp
2100 The
2101 .Fl rR
2102 options do not recursively destroy the child snapshots of a recursive snapshot.
2103 Only direct snapshots of the specified filesystem are destroyed by either of
2104 these options.
2105 To completely roll back a recursive snapshot, you must rollback the individual
2106 child snapshots.
2107 .Bl -tag -width "-R"
2108 .It Fl R
2109 Destroy any more recent snapshots and bookmarks, as well as any clones of those
2110 snapshots.
2111 .It Fl f
2112 Used with the
2113 .Fl R
2114 option to force an unmount of any clone file systems that are to be destroyed.
2115 .It Fl r
2116 Destroy any snapshots and bookmarks more recent than the one specified.
2117 .El
2118 .It Xo
2119 .Nm
2120 .Cm clone
2121 .Op Fl p
2122 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
2123 .Ar snapshot Ar filesystem Ns | Ns Ar volume
2124 .Xc
2125 Creates a clone of the given snapshot.
2126 See the
2127 .Sx Clones
2128 section for details.
2129 The target dataset can be located anywhere in the ZFS hierarchy, and is created
2130 as the same type as the original.
2131 .Bl -tag -width "-o"
2132 .It Fl o Ar property Ns = Ns Ar value
2133 Sets the specified property; see
2134 .Nm zfs Cm create
2135 for details.
2136 .It Fl p
2137 Creates all the non-existing parent datasets.
2138 Datasets created in this manner are automatically mounted according to the
2139 .Sy mountpoint
2140 property inherited from their parent.
2141 If the target filesystem or volume already exists, the operation completes
2142 successfully.
2143 .El
2144 .It Xo
2145 .Nm
2146 .Cm promote
2147 .Ar clone-filesystem
2148 .Xc
2149 Promotes a clone file system to no longer be dependent on its
2150 .Qq origin
2151 snapshot.
2152 This makes it possible to destroy the file system that the clone was created
2153 from.
2154 The clone parent-child dependency relationship is reversed, so that the origin
2155 file system becomes a clone of the specified file system.
2156 .Pp
2157 The snapshot that was cloned, and any snapshots previous to this snapshot, are
2158 now owned by the promoted clone.
2159 The space they use moves from the origin file system to the promoted clone, so
2160 enough space must be available to accommodate these snapshots.
2161 No new space is consumed by this operation, but the space accounting is
2162 adjusted.
2163 The promoted clone must not have any conflicting snapshot names of its own.
2164 The
2165 .Cm rename
2166 subcommand can be used to rename any conflicting snapshots.
2167 .It Xo
2168 .Nm
2169 .Cm rename
2170 .Op Fl f
2171 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
2172 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
2173 .Xc
2174 .It Xo
2175 .Nm
2176 .Cm rename
2177 .Op Fl fp
2178 .Ar filesystem Ns | Ns Ar volume
2179 .Ar filesystem Ns | Ns Ar volume
2180 .Xc
2181 Renames the given dataset.
2182 The new target can be located anywhere in the ZFS hierarchy, with the exception
2183 of snapshots.
2184 Snapshots can only be renamed within the parent file system or volume.
2185 When renaming a snapshot, the parent file system of the snapshot does not need
2186 to be specified as part of the second argument.
2187 Renamed file systems can inherit new mount points, in which case they are
2188 unmounted and remounted at the new mount point.
2189 .Bl -tag -width "-a"
2190 .It Fl f
2191 Force unmount any filesystems that need to be unmounted in the process.
2192 .It Fl p
2193 Creates all the nonexistent parent datasets.
2194 Datasets created in this manner are automatically mounted according to the
2195 .Sy mountpoint
2196 property inherited from their parent.
2197 .El
2198 .It Xo
2199 .Nm
2200 .Cm rename
2201 .Fl r
2202 .Ar snapshot Ar snapshot
2203 .Xc
2204 Recursively rename the snapshots of all descendent datasets.
2205 Snapshots are the only dataset that can be renamed recursively.
2206 .It Xo
2207 .Nm
2208 .Cm list
2209 .Op Fl r Ns | Ns Fl d Ar depth
2210 .Op Fl Hp
2211 .Oo Fl o Ar property Ns Oo , Ns Ar property Oc Ns ... Oc
2212 .Oo Fl s Ar property Oc Ns ...
2213 .Oo Fl S Ar property Oc Ns ...
2214 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
2215 .Oo Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Oc Ns ...
2216 .Xc
2217 Lists the property information for the given datasets in tabular form.
2218 If specified, you can list property information by the absolute pathname or the
2219 relative pathname.
2220 By default, all file systems and volumes are displayed.
2221 Snapshots are displayed if the
2222 .Sy listsnaps
2223 property is
2224 .Sy on
2225 .Po the default is
2226 .Sy off
2227 .Pc .
2228 The following fields are displayed,
2229 .Sy name Ns \&, Ns Sy used Ns \&, Ns Sy available Ns \&, Ns Sy referenced Ns \&, Ns
2230 .Sy mountpoint .
2231 .Bl -tag -width "-H"
2232 .It Fl H
2233 Used for scripting mode.
2234 Do not print headers and separate fields by a single tab instead of arbitrary
2235 white space.
2236 .It Fl S Ar property
2237 Same as the
2238 .Fl s
2239 option, but sorts by property in descending order.
2240 .It Fl d Ar depth
2241 Recursively display any children of the dataset, limiting the recursion to
2242 .Ar depth .
2243 A
2244 .Ar depth
2245 of
2246 .Sy 1
2247 will display only the dataset and its direct children.
2248 .It Fl o Ar property
2249 A comma-separated list of properties to display.
2250 The property must be:
2251 .Bl -bullet
2252 .It
2253 One of the properties described in the
2254 .Sx Native Properties
2255 section
2256 .It
2257 A user property
2258 .It
2259 The value
2260 .Sy name
2261 to display the dataset name
2262 .It
2263 The value
2264 .Sy space
2265 to display space usage properties on file systems and volumes.
2266 This is a shortcut for specifying
2267 .Fl o Sy name Ns \&, Ns Sy avail Ns \&, Ns Sy used Ns \&, Ns Sy usedsnap Ns \&, Ns
2268 .Sy usedds Ns \&, Ns Sy usedrefreserv Ns \&, Ns Sy usedchild Fl t
2269 .Sy filesystem Ns \&, Ns Sy volume
2270 syntax.
2271 .El
2272 .It Fl p
2273 Display numbers in parsable
2274 .Pq exact
2275 values.
2276 .It Fl r
2277 Recursively display any children of the dataset on the command line.
2278 .It Fl s Ar property
2279 A property for sorting the output by column in ascending order based on the
2280 value of the property.
2281 The property must be one of the properties described in the
2282 .Sx Properties
2283 section, or the special value
2284 .Sy name
2285 to sort by the dataset name.
2286 Multiple properties can be specified at one time using multiple
2287 .Fl s
2288 property options.
2289 Multiple
2290 .Fl s
2291 options are evaluated from left to right in decreasing order of importance.
2292 The following is a list of sorting criteria:
2293 .Bl -bullet
2294 .It
2295 Numeric types sort in numeric order.
2296 .It
2297 String types sort in alphabetical order.
2298 .It
2299 Types inappropriate for a row sort that row to the literal bottom, regardless of
2300 the specified ordering.
2301 .El
2302 .Pp
2303 If no sorting options are specified the existing behavior of
2304 .Nm zfs Cm list
2305 is preserved.
2306 .It Fl t Ar type
2307 A comma-separated list of types to display, where
2308 .Ar type
2309 is one of
2310 .Sy filesystem ,
2311 .Sy snapshot ,
2312 .Sy volume ,
2313 .Sy bookmark ,
2314 or
2315 .Sy all .
2316 For example, specifying
2317 .Fl t Sy snapshot
2318 displays only snapshots.
2319 .El
2320 .It Xo
2321 .Nm
2322 .Cm set
2323 .Ar property Ns = Ns Ar value Oo Ar property Ns = Ns Ar value Oc Ns ...
2324 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
2325 .Xc
2326 Sets the property or list of properties to the given value(s) for each dataset.
2327 Only some properties can be edited.
2328 See the
2329 .Sx Properties
2330 section for more information on what properties can be set and acceptable
2331 values.
2332 Numeric values can be specified as exact values, or in a human-readable form
2333 with a suffix of
2334 .Sy B , K , M , G , T , P , E , Z
2335 .Po for bytes, kilobytes, megabytes, gigabytes, terabytes, petabytes, exabytes,
2336 or zettabytes, respectively
2337 .Pc .
2338 User properties can be set on snapshots.
2339 For more information, see the
2340 .Sx User Properties
2341 section.
2342 .It Xo
2343 .Nm
2344 .Cm get
2345 .Op Fl r Ns | Ns Fl d Ar depth
2346 .Op Fl Hp
2347 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
2348 .Oo Fl s Ar source Ns Oo , Ns Ar source Oc Ns ... Oc
2349 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
2350 .Cm all | Ar property Ns Oo , Ns Ar property Oc Ns ...
2351 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns | Ns Ar bookmark Ns ...
2352 .Xc
2353 Displays properties for the given datasets.
2354 If no datasets are specified, then the command displays properties for all
2355 datasets on the system.
2356 For each property, the following columns are displayed:
2357 .Bd -literal
2358 name Dataset name
2359 property Property name
2360 value Property value
2361 source Property source. Can either be local, default,
2362 temporary, inherited, or none (-).
2363 .Ed
2364 .Pp
2365 All columns are displayed by default, though this can be controlled by using the
2366 .Fl o
2367 option.
2368 This command takes a comma-separated list of properties as described in the
2369 .Sx Native Properties
2370 and
2371 .Sx User Properties
2372 sections.
2373 .Pp
2374 The special value
2375 .Sy all
2376 can be used to display all properties that apply to the given dataset's type
2377 .Pq filesystem, volume, snapshot, or bookmark .
2378 .Bl -tag -width "-H"
2379 .It Fl H
2380 Display output in a form more easily parsed by scripts.
2381 Any headers are omitted, and fields are explicitly separated by a single tab
2382 instead of an arbitrary amount of space.
2383 .It Fl d Ar depth
2384 Recursively display any children of the dataset, limiting the recursion to
2385 .Ar depth .
2386 A depth of
2387 .Sy 1
2388 will display only the dataset and its direct children.
2389 .It Fl o Ar field
2390 A comma-separated list of columns to display.
2391 .Sy name Ns \&, Ns Sy property Ns \&, Ns Sy value Ns \&, Ns Sy source
2392 is the default value.
2393 .It Fl p
2394 Display numbers in parsable
2395 .Pq exact
2396 values.
2397 .It Fl r
2398 Recursively display properties for any children.
2399 .It Fl s Ar source
2400 A comma-separated list of sources to display.
2401 Those properties coming from a source other than those in this list are ignored.
2402 Each source must be one of the following:
2403 .Sy local ,
2404 .Sy default ,
2405 .Sy inherited ,
2406 .Sy temporary ,
2407 and
2408 .Sy none .
2409 The default value is all sources.
2410 .It Fl t Ar type
2411 A comma-separated list of types to display, where
2412 .Ar type
2413 is one of
2414 .Sy filesystem ,
2415 .Sy snapshot ,
2416 .Sy volume ,
2417 .Sy bookmark ,
2418 or
2419 .Sy all .
2420 .El
2421 .It Xo
2422 .Nm
2423 .Cm inherit
2424 .Op Fl rS
2425 .Ar property Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
2426 .Xc
2427 Clears the specified property, causing it to be inherited from an ancestor,
2428 restored to default if no ancestor has the property set, or with the
2429 .Fl S
2430 option reverted to the received value if one exists.
2431 See the
2432 .Sx Properties
2433 section for a listing of default values, and details on which properties can be
2434 inherited.
2435 .Bl -tag -width "-r"
2436 .It Fl r
2437 Recursively inherit the given property for all children.
2438 .It Fl S
2439 Revert the property to the received value if one exists; otherwise operate as
2440 if the
2441 .Fl S
2442 option was not specified.
2443 .El
2444 .It Xo
2445 .Nm
2446 .Cm remap
2447 .Ar filesystem Ns | Ns Ar volume
2448 .Xc
2449 Remap the indirect blocks in the given fileystem or volume so that they no
2450 longer reference blocks on previously removed vdevs and we can eventually
2451 shrink the size of the indirect mapping objects for the previously removed
2452 vdevs. Note that remapping all blocks might not be possible and that
2453 references from snapshots will still exist and cannot be remapped.
2454 .It Xo
2455 .Nm
2456 .Cm upgrade
2457 .Xc
2458 Displays a list of file systems that are not the most recent version.
2459 .It Xo
2460 .Nm
2461 .Cm upgrade
2462 .Fl v
2463 .Xc
2464 Displays a list of currently supported file system versions.
2465 .It Xo
2466 .Nm
2467 .Cm upgrade
2468 .Op Fl r
2469 .Op Fl V Ar version
2470 .Fl a | Ar filesystem
2471 .Xc
2472 Upgrades file systems to a new on-disk version.
2473 Once this is done, the file systems will no longer be accessible on systems
2474 running older versions of the software.
2475 .Nm zfs Cm send
2476 streams generated from new snapshots of these file systems cannot be accessed on
2477 systems running older versions of the software.
2478 .Pp
2479 In general, the file system version is independent of the pool version.
2480 See
2481 .Xr zpool 1M
2482 for information on the
2483 .Nm zpool Cm upgrade
2484 command.
2485 .Pp
2486 In some cases, the file system version and the pool version are interrelated and
2487 the pool version must be upgraded before the file system version can be
2488 upgraded.
2489 .Bl -tag -width "-V"
2490 .It Fl V Ar version
2491 Upgrade to the specified
2492 .Ar version .
2493 If the
2494 .Fl V
2495 flag is not specified, this command upgrades to the most recent version.
2496 This
2497 option can only be used to increase the version number, and only up to the most
2498 recent version supported by this software.
2499 .It Fl a
2500 Upgrade all file systems on all imported pools.
2501 .It Ar filesystem
2502 Upgrade the specified file system.
2503 .It Fl r
2504 Upgrade the specified file system and all descendent file systems.
2505 .El
2506 .It Xo
2507 .Nm
2508 .Cm userspace
2509 .Op Fl Hinp
2510 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
2511 .Oo Fl s Ar field Oc Ns ...
2512 .Oo Fl S Ar field Oc Ns ...
2513 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
2514 .Ar filesystem Ns | Ns Ar snapshot
2515 .Xc
2516 Displays space consumed by, and quotas on, each user in the specified filesystem
2517 or snapshot.
2518 This corresponds to the
2519 .Sy userused@ Ns Em user
2520 and
2521 .Sy userquota@ Ns Em user
2522 properties.
2523 .Bl -tag -width "-H"
2524 .It Fl H
2525 Do not print headers, use tab-delimited output.
2526 .It Fl S Ar field
2527 Sort by this field in reverse order.
2528 See
2529 .Fl s .
2530 .It Fl i
2531 Translate SID to POSIX ID.
2532 The POSIX ID may be ephemeral if no mapping exists.
2533 Normal POSIX interfaces
2534 .Po for example,
2535 .Xr stat 2 ,
2536 .Nm ls Fl l
2537 .Pc
2538 perform this translation, so the
2539 .Fl i
2540 option allows the output from
2541 .Nm zfs Cm userspace
2542 to be compared directly with those utilities.
2543 However,
2544 .Fl i
2545 may lead to confusion if some files were created by an SMB user before a
2546 SMB-to-POSIX name mapping was established.
2547 In such a case, some files will be owned by the SMB entity and some by the POSIX
2548 entity.
2549 However, the
2550 .Fl i
2551 option will report that the POSIX entity has the total usage and quota for both.
2552 .It Fl n
2553 Print numeric ID instead of user/group name.
2554 .It Fl o Ar field Ns Oo , Ns Ar field Oc Ns ...
2555 Display only the specified fields from the following set:
2556 .Sy type ,
2557 .Sy name ,
2558 .Sy used ,
2559 .Sy quota .
2560 The default is to display all fields.
2561 .It Fl p
2562 Use exact
2563 .Pq parsable
2564 numeric output.
2565 .It Fl s Ar field
2566 Sort output by this field.
2567 The
2568 .Fl s
2569 and
2570 .Fl S
2571 flags may be specified multiple times to sort first by one field, then by
2572 another.
2573 The default is
2574 .Fl s Sy type Fl s Sy name .
2575 .It Fl t Ar type Ns Oo , Ns Ar type Oc Ns ...
2576 Print only the specified types from the following set:
2577 .Sy all ,
2578 .Sy posixuser ,
2579 .Sy smbuser ,
2580 .Sy posixgroup ,
2581 .Sy smbgroup .
2582 The default is
2583 .Fl t Sy posixuser Ns \&, Ns Sy smbuser .
2584 The default can be changed to include group types.
2585 .El
2586 .It Xo
2587 .Nm
2588 .Cm groupspace
2589 .Op Fl Hinp
2590 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
2591 .Oo Fl s Ar field Oc Ns ...
2592 .Oo Fl S Ar field Oc Ns ...
2593 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
2594 .Ar filesystem Ns | Ns Ar snapshot
2595 .Xc
2596 Displays space consumed by, and quotas on, each group in the specified
2597 filesystem or snapshot.
2598 This subcommand is identical to
2599 .Nm zfs Cm userspace ,
2600 except that the default types to display are
2601 .Fl t Sy posixgroup Ns \&, Ns Sy smbgroup .
2602 .It Xo
2603 .Nm
2604 .Cm mount
2605 .Xc
2606 Displays all ZFS file systems currently mounted.
2607 .It Xo
2608 .Nm
2609 .Cm mount
2610 .Op Fl Ov
2611 .Op Fl o Ar options
2612 .Fl a | Ar filesystem
2613 .Xc
2614 Mounts ZFS file systems.
2615 .Bl -tag -width "-O"
2616 .It Fl O
2617 Perform an overlay mount.
2618 See
2619 .Xr mount 1M
2620 for more information.
2621 .It Fl a
2622 Mount all available ZFS file systems.
2623 Invoked automatically as part of the boot process.
2624 .It Ar filesystem
2625 Mount the specified filesystem.
2626 .It Fl o Ar options
2627 An optional, comma-separated list of mount options to use temporarily for the
2628 duration of the mount.
2629 See the
2630 .Sx Temporary Mount Point Properties
2631 section for details.
2632 .It Fl v
2633 Report mount progress.
2634 .El
2635 .It Xo
2636 .Nm
2637 .Cm unmount
2638 .Op Fl f
2639 .Fl a | Ar filesystem Ns | Ns Ar mountpoint
2640 .Xc
2641 Unmounts currently mounted ZFS file systems.
2642 .Bl -tag -width "-a"
2643 .It Fl a
2644 Unmount all available ZFS file systems.
2645 Invoked automatically as part of the shutdown process.
2646 .It Ar filesystem Ns | Ns Ar mountpoint
2647 Unmount the specified filesystem.
2648 The command can also be given a path to a ZFS file system mount point on the
2649 system.
2650 .It Fl f
2651 Forcefully unmount the file system, even if it is currently in use.
2652 .El
2653 .It Xo
2654 .Nm
2655 .Cm share
2656 .Fl a | Ar filesystem
2657 .Xc
2658 Shares available ZFS file systems.
2659 .Bl -tag -width "-a"
2660 .It Fl a
2661 Share all available ZFS file systems.
2662 Invoked automatically as part of the boot process.
2663 .It Ar filesystem
2664 Share the specified filesystem according to the
2665 .Sy sharenfs
2666 and
2667 .Sy sharesmb
2668 properties.
2669 File systems are shared when the
2670 .Sy sharenfs
2671 or
2672 .Sy sharesmb
2673 property is set.
2674 .El
2675 .It Xo
2676 .Nm
2677 .Cm unshare
2678 .Fl a | Ar filesystem Ns | Ns Ar mountpoint
2679 .Xc
2680 Unshares currently shared ZFS file systems.
2681 .Bl -tag -width "-a"
2682 .It Fl a
2683 Unshare all available ZFS file systems.
2684 Invoked automatically as part of the shutdown process.
2685 .It Ar filesystem Ns | Ns Ar mountpoint
2686 Unshare the specified filesystem.
2687 The command can also be given a path to a ZFS file system shared on the system.
2688 .El
2689 .It Xo
2690 .Nm
2691 .Cm bookmark
2692 .Ar snapshot bookmark
2693 .Xc
2694 Creates a bookmark of the given snapshot.
2695 Bookmarks mark the point in time when the snapshot was created, and can be used
2696 as the incremental source for a
2697 .Nm zfs Cm send
2698 command.
2699 .Pp
2700 This feature must be enabled to be used.
2701 See
2702 .Xr zpool-features 5
2703 for details on ZFS feature flags and the
2704 .Sy bookmarks
2705 feature.
2706 .It Xo
2707 .Nm
2708 .Cm send
2709 .Op Fl DLPRcenpv
2710 .Op Oo Fl I Ns | Ns Fl i Oc Ar snapshot
2711 .Ar snapshot
2712 .Xc
2713 Creates a stream representation of the second
2714 .Ar snapshot ,
2715 which is written to standard output.
2716 The output can be redirected to a file or to a different system
2717 .Po for example, using
2718 .Xr ssh 1
2719 .Pc .
2720 By default, a full stream is generated.
2721 .Bl -tag -width "-D"
2722 .It Fl D, -dedup
2723 Generate a deduplicated stream.
2724 Blocks which would have been sent multiple times in the send stream will only be
2725 sent once.
2726 The receiving system must also support this feature to receive a deduplicated
2727 stream.
2728 This flag can be used regardless of the dataset's
2729 .Sy dedup
2730 property, but performance will be much better if the filesystem uses a
2731 dedup-capable checksum
2732 .Po for example,
2733 .Sy sha256
2734 .Pc .
2735 .It Fl I Ar snapshot
2736 Generate a stream package that sends all intermediary snapshots from the first
2737 snapshot to the second snapshot.
2738 For example,
2739 .Fl I Em @a Em fs@d
2740 is similar to
2741 .Fl i Em @a Em fs@b Ns \&; Fl i Em @b Em fs@c Ns \&; Fl i Em @c Em fs@d .
2742 The incremental source may be specified as with the
2743 .Fl i
2744 option.
2745 .It Fl L, -large-block
2746 Generate a stream which may contain blocks larger than 128KB.
2747 This flag has no effect if the
2748 .Sy large_blocks
2749 pool feature is disabled, or if the
2750 .Sy recordsize
2751 property of this filesystem has never been set above 128KB.
2752 The receiving system must have the
2753 .Sy large_blocks
2754 pool feature enabled as well.
2755 See
2756 .Xr zpool-features 5
2757 for details on ZFS feature flags and the
2758 .Sy large_blocks
2759 feature.
2760 .It Fl P, -parsable
2761 Print machine-parsable verbose information about the stream package generated.
2762 .It Fl R, -replicate
2763 Generate a replication stream package, which will replicate the specified
2764 file system, and all descendent file systems, up to the named snapshot.
2765 When received, all properties, snapshots, descendent file systems, and clones
2766 are preserved.
2767 .Pp
2768 If the
2769 .Fl i
2770 or
2771 .Fl I
2772 flags are used in conjunction with the
2773 .Fl R
2774 flag, an incremental replication stream is generated.
2775 The current values of properties, and current snapshot and file system names are
2776 set when the stream is received.
2777 If the
2778 .Fl F
2779 flag is specified when this stream is received, snapshots and file systems that
2780 do not exist on the sending side are destroyed.
2781 .It Fl e, -embed
2782 Generate a more compact stream by using
2783 .Sy WRITE_EMBEDDED
2784 records for blocks which are stored more compactly on disk by the
2785 .Sy embedded_data
2786 pool feature.
2787 This flag has no effect if the
2788 .Sy embedded_data
2789 feature is disabled.
2790 The receiving system must have the
2791 .Sy embedded_data
2792 feature enabled.
2793 If the
2794 .Sy lz4_compress
2795 feature is active on the sending system, then the receiving system must have
2796 that feature enabled as well.
2797 See
2798 .Xr zpool-features 5
2799 for details on ZFS feature flags and the
2800 .Sy embedded_data
2801 feature.
2802 .It Fl c, -compressed
2803 Generate a more compact stream by using compressed WRITE records for blocks
2804 which are compressed on disk and in memory
2805 .Po see the
2806 .Sy compression
2807 property for details
2808 .Pc .
2809 If the
2810 .Sy lz4_compress
2811 feature is active on the sending system, then the receiving system must have
2812 that feature enabled as well.
2813 If the
2814 .Sy large_blocks
2815 feature is enabled on the sending system but the
2816 .Fl L
2817 option is not supplied in conjunction with
2818 .Fl c ,
2819 then the data will be decompressed before sending so it can be split into
2820 smaller block sizes.
2821 .It Fl i Ar snapshot
2822 Generate an incremental stream from the first
2823 .Ar snapshot
2824 .Pq the incremental source
2825 to the second
2826 .Ar snapshot
2827 .Pq the incremental target .
2828 The incremental source can be specified as the last component of the snapshot
2829 name
2830 .Po the
2831 .Sy @
2832 character and following
2833 .Pc
2834 and it is assumed to be from the same file system as the incremental target.
2835 .Pp
2836 If the destination is a clone, the source may be the origin snapshot, which must
2837 be fully specified
2838 .Po for example,
2839 .Em pool/fs@origin ,
2840 not just
2841 .Em @origin
2842 .Pc .
2843 .It Fl n, -dryrun
2844 Do a dry-run
2845 .Pq Qq No-op
2846 send.
2847 Do not generate any actual send data.
2848 This is useful in conjunction with the
2849 .Fl v
2850 or
2851 .Fl P
2852 flags to determine what data will be sent.
2853 In this case, the verbose output will be written to standard output
2854 .Po contrast with a non-dry-run, where the stream is written to standard output
2855 and the verbose output goes to standard error
2856 .Pc .
2857 .It Fl p, -props
2858 Include the dataset's properties in the stream.
2859 This flag is implicit when
2860 .Fl R
2861 is specified.
2862 The receiving system must also support this feature.
2863 .It Fl v, -verbose
2864 Print verbose information about the stream package generated.
2865 This information includes a per-second report of how much data has been sent.
2866 .Pp
2867 The format of the stream is committed.
2868 You will be able to receive your streams on future versions of ZFS .
2869 .El
2870 .It Xo
2871 .Nm
2872 .Cm send
2873 .Op Fl Lce
2874 .Op Fl i Ar snapshot Ns | Ns Ar bookmark
2875 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
2876 .Xc
2877 Generate a send stream, which may be of a filesystem, and may be incremental
2878 from a bookmark.
2879 If the destination is a filesystem or volume, the pool must be read-only, or the
2880 filesystem must not be mounted.
2881 When the stream generated from a filesystem or volume is received, the default
2882 snapshot name will be
2883 .Qq --head-- .
2884 .Bl -tag -width "-L"
2885 .It Fl L, -large-block
2886 Generate a stream which may contain blocks larger than 128KB.
2887 This flag has no effect if the
2888 .Sy large_blocks
2889 pool feature is disabled, or if the
2890 .Sy recordsize
2891 property of this filesystem has never been set above 128KB.
2892 The receiving system must have the
2893 .Sy large_blocks
2894 pool feature enabled as well.
2895 See
2896 .Xr zpool-features 5
2897 for details on ZFS feature flags and the
2898 .Sy large_blocks
2899 feature.
2900 .It Fl c, -compressed
2901 Generate a more compact stream by using compressed WRITE records for blocks
2902 which are compressed on disk and in memory
2903 .Po see the
2904 .Sy compression
2905 property for details
2906 .Pc .
2907 If the
2908 .Sy lz4_compress
2909 feature is active on the sending system, then the receiving system must have
2910 that feature enabled as well.
2911 If the
2912 .Sy large_blocks
2913 feature is enabled on the sending system but the
2914 .Fl L
2915 option is not supplied in conjunction with
2916 .Fl c ,
2917 then the data will be decompressed before sending so it can be split into
2918 smaller block sizes.
2919 .It Fl e, -embed
2920 Generate a more compact stream by using
2921 .Sy WRITE_EMBEDDED
2922 records for blocks which are stored more compactly on disk by the
2923 .Sy embedded_data
2924 pool feature.
2925 This flag has no effect if the
2926 .Sy embedded_data
2927 feature is disabled.
2928 The receiving system must have the
2929 .Sy embedded_data
2930 feature enabled.
2931 If the
2932 .Sy lz4_compress
2933 feature is active on the sending system, then the receiving system must have
2934 that feature enabled as well.
2935 See
2936 .Xr zpool-features 5
2937 for details on ZFS feature flags and the
2938 .Sy embedded_data
2939 feature.
2940 .It Fl i Ar snapshot Ns | Ns Ar bookmark
2941 Generate an incremental send stream.
2942 The incremental source must be an earlier snapshot in the destination's history.
2943 It will commonly be an earlier snapshot in the destination's file system, in
2944 which case it can be specified as the last component of the name
2945 .Po the
2946 .Sy #
2947 or
2948 .Sy @
2949 character and following
2950 .Pc .
2951 .Pp
2952 If the incremental target is a clone, the incremental source can be the origin
2953 snapshot, or an earlier snapshot in the origin's filesystem, or the origin's
2954 origin, etc.
2955 .El
2956 .It Xo
2957 .Nm
2958 .Cm send
2959 .Op Fl Penv
2960 .Fl t
2961 .Ar receive_resume_token
2962 .Xc
2963 Creates a send stream which resumes an interrupted receive.
2964 The
2965 .Ar receive_resume_token
2966 is the value of this property on the filesystem or volume that was being
2967 received into.
2968 See the documentation for
2969 .Sy zfs receive -s
2970 for more details.
2971 .It Xo
2972 .Nm
2973 .Cm receive
2974 .Op Fl Fnsuv
2975 .Op Fl o Sy origin Ns = Ns Ar snapshot
2976 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
2977 .Xc
2978 .It Xo
2979 .Nm
2980 .Cm receive
2981 .Op Fl Fnsuv
2982 .Op Fl d Ns | Ns Fl e
2983 .Op Fl o Sy origin Ns = Ns Ar snapshot
2984 .Ar filesystem
2985 .Xc
2986 Creates a snapshot whose contents are as specified in the stream provided on
2987 standard input.
2988 If a full stream is received, then a new file system is created as well.
2989 Streams are created using the
2990 .Nm zfs Cm send
2991 subcommand, which by default creates a full stream.
2992 .Nm zfs Cm recv
2993 can be used as an alias for
2994 .Nm zfs Cm receive.
2995 .Pp
2996 If an incremental stream is received, then the destination file system must
2997 already exist, and its most recent snapshot must match the incremental stream's
2998 source.
2999 For
3000 .Sy zvols ,
3001 the destination device link is destroyed and recreated, which means the
3002 .Sy zvol
3003 cannot be accessed during the
3004 .Cm receive
3005 operation.
3006 .Pp
3007 When a snapshot replication package stream that is generated by using the
3008 .Nm zfs Cm send Fl R
3009 command is received, any snapshots that do not exist on the sending location are
3010 destroyed by using the
3011 .Nm zfs Cm destroy Fl d
3012 command.
3013 .Pp
3014 The name of the snapshot
3015 .Pq and file system, if a full stream is received
3016 that this subcommand creates depends on the argument type and the use of the
3017 .Fl d
3018 or
3019 .Fl e
3020 options.
3021 .Pp
3022 If the argument is a snapshot name, the specified
3023 .Ar snapshot
3024 is created.
3025 If the argument is a file system or volume name, a snapshot with the same name
3026 as the sent snapshot is created within the specified
3027 .Ar filesystem
3028 or
3029 .Ar volume .
3030 If neither of the
3031 .Fl d
3032 or
3033 .Fl e
3034 options are specified, the provided target snapshot name is used exactly as
3035 provided.
3036 .Pp
3037 The
3038 .Fl d
3039 and
3040 .Fl e
3041 options cause the file system name of the target snapshot to be determined by
3042 appending a portion of the sent snapshot's name to the specified target
3043 .Ar filesystem .
3044 If the
3045 .Fl d
3046 option is specified, all but the first element of the sent snapshot's file
3047 system path
3048 .Pq usually the pool name
3049 is used and any required intermediate file systems within the specified one are
3050 created.
3051 If the
3052 .Fl e
3053 option is specified, then only the last element of the sent snapshot's file
3054 system name
3055 .Pq i.e. the name of the source file system itself
3056 is used as the target file system name.
3057 .Bl -tag -width "-F"
3058 .It Fl F
3059 Force a rollback of the file system to the most recent snapshot before
3060 performing the receive operation.
3061 If receiving an incremental replication stream
3062 .Po for example, one generated by
3063 .Nm zfs Cm send Fl R Op Fl i Ns | Ns Fl I
3064 .Pc ,
3065 destroy snapshots and file systems that do not exist on the sending side.
3066 .It Fl d
3067 Discard the first element of the sent snapshot's file system name, using the
3068 remaining elements to determine the name of the target file system for the new
3069 snapshot as described in the paragraph above.
3070 .It Fl e
3071 Discard all but the last element of the sent snapshot's file system name, using
3072 that element to determine the name of the target file system for the new
3073 snapshot as described in the paragraph above.
3074 .It Fl n
3075 Do not actually receive the stream.
3076 This can be useful in conjunction with the
3077 .Fl v
3078 option to verify the name the receive operation would use.
3079 .It Fl o Sy origin Ns = Ns Ar snapshot
3080 Forces the stream to be received as a clone of the given snapshot.
3081 If the stream is a full send stream, this will create the filesystem
3082 described by the stream as a clone of the specified snapshot.
3083 Which snapshot was specified will not affect the success or failure of the
3084 receive, as long as the snapshot does exist.
3085 If the stream is an incremental send stream, all the normal verification will be
3086 performed.
3087 .It Fl u
3088 File system that is associated with the received stream is not mounted.
3089 .It Fl v
3090 Print verbose information about the stream and the time required to perform the
3091 receive operation.
3092 .It Fl s
3093 If the receive is interrupted, save the partially received state, rather
3094 than deleting it.
3095 Interruption may be due to premature termination of the stream
3096 .Po e.g. due to network failure or failure of the remote system
3097 if the stream is being read over a network connection
3098 .Pc ,
3099 a checksum error in the stream, termination of the
3100 .Nm zfs Cm receive
3101 process, or unclean shutdown of the system.
3102 .Pp
3103 The receive can be resumed with a stream generated by
3104 .Nm zfs Cm send Fl t Ar token ,
3105 where the
3106 .Ar token
3107 is the value of the
3108 .Sy receive_resume_token
3109 property of the filesystem or volume which is received into.
3110 .Pp
3111 To use this flag, the storage pool must have the
3112 .Sy extensible_dataset
3113 feature enabled.
3114 See
3115 .Xr zpool-features 5
3116 for details on ZFS feature flags.
3117 .El
3118 .It Xo
3119 .Nm
3120 .Cm receive
3121 .Fl A
3122 .Ar filesystem Ns | Ns Ar volume
3123 .Xc
3124 Abort an interrupted
3125 .Nm zfs Cm receive Fl s ,
3126 deleting its saved partially received state.
3127 .It Xo
3128 .Nm
3129 .Cm allow
3130 .Ar filesystem Ns | Ns Ar volume
3131 .Xc
3132 Displays permissions that have been delegated on the specified filesystem or
3133 volume.
3134 See the other forms of
3135 .Nm zfs Cm allow
3136 for more information.
3137 .It Xo
3138 .Nm
3139 .Cm allow
3140 .Op Fl dglu
3141 .Ar user Ns | Ns Ar group Ns Oo , Ns Ar user Ns | Ns Ar group Oc Ns ...
3142 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
3143 .Ar setname Oc Ns ...
3144 .Ar filesystem Ns | Ns Ar volume
3145 .Xc
3146 .It Xo
3147 .Nm
3148 .Cm allow
3149 .Op Fl dl
3150 .Fl e Ns | Ns Sy everyone
3151 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
3152 .Ar setname Oc Ns ...
3153 .Ar filesystem Ns | Ns Ar volume
3154 .Xc
3155 Delegates ZFS administration permission for the file systems to non-privileged
3156 users.
3157 .Bl -tag -width "-d"
3158 .It Fl d
3159 Allow only for the descendent file systems.
3160 .It Fl e Ns | Ns Sy everyone
3161 Specifies that the permissions be delegated to everyone.
3162 .It Fl g Ar group Ns Oo , Ns Ar group Oc Ns ...
3163 Explicitly specify that permissions are delegated to the group.
3164 .It Fl l
3165 Allow
3166 .Qq locally
3167 only for the specified file system.
3168 .It Fl u Ar user Ns Oo , Ns Ar user Oc Ns ...
3169 Explicitly specify that permissions are delegated to the user.
3170 .It Ar user Ns | Ns Ar group Ns Oo , Ns Ar user Ns | Ns Ar group Oc Ns ...
3171 Specifies to whom the permissions are delegated.
3172 Multiple entities can be specified as a comma-separated list.
3173 If neither of the
3174 .Fl gu
3175 options are specified, then the argument is interpreted preferentially as the
3176 keyword
3177 .Sy everyone ,
3178 then as a user name, and lastly as a group name.
3179 To specify a user or group named
3180 .Qq everyone ,
3181 use the
3182 .Fl g
3183 or
3184 .Fl u
3185 options.
3186 To specify a group with the same name as a user, use the
3187 .Fl g
3188 options.
3189 .It Xo
3190 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
3191 .Ar setname Oc Ns ...
3192 .Xc
3193 The permissions to delegate.
3194 Multiple permissions may be specified as a comma-separated list.
3195 Permission names are the same as ZFS subcommand and property names.
3196 See the property list below.
3197 Property set names, which begin with
3198 .Sy @ ,
3199 may be specified.
3200 See the
3201 .Fl s
3202 form below for details.
3203 .El
3204 .Pp
3205 If neither of the
3206 .Fl dl
3207 options are specified, or both are, then the permissions are allowed for the
3208 file system or volume, and all of its descendents.
3209 .Pp
3210 Permissions are generally the ability to use a ZFS subcommand or change a ZFS
3211 property.
3212 The following permissions are available:
3213 .Bd -literal
3214 NAME TYPE NOTES
3215 allow subcommand Must also have the permission that is
3216 being allowed
3217 clone subcommand Must also have the 'create' ability and
3218 'mount' ability in the origin file system
3219 create subcommand Must also have the 'mount' ability
3220 destroy subcommand Must also have the 'mount' ability
3221 diff subcommand Allows lookup of paths within a dataset
3222 given an object number, and the ability
3223 to create snapshots necessary to
3224 'zfs diff'.
3225 mount subcommand Allows mount/umount of ZFS datasets
3226 promote subcommand Must also have the 'mount' and 'promote'
3227 ability in the origin file system
3228 receive subcommand Must also have the 'mount' and 'create'
3229 ability
3230 rename subcommand Must also have the 'mount' and 'create'
3231 ability in the new parent
3232 rollback subcommand Must also have the 'mount' ability
3233 send subcommand
3234 share subcommand Allows sharing file systems over NFS
3235 or SMB protocols
3236 snapshot subcommand Must also have the 'mount' ability
3237
3238 groupquota other Allows accessing any groupquota@...
3239 property
3240 groupused other Allows reading any groupused@... property
3241 userprop other Allows changing any user property
3242 userquota other Allows accessing any userquota@...
3243 property
3244 userused other Allows reading any userused@... property
3245
3246 aclinherit property
3247 aclmode property
3248 atime property
3249 canmount property
3250 casesensitivity property
3251 checksum property
3252 compression property
3253 copies property
3254 devices property
3255 exec property
3256 filesystem_limit property
3257 mountpoint property
3258 nbmand property
3259 normalization property
3260 primarycache property
3261 quota property
3262 readonly property
3263 recordsize property
3264 refquota property
3265 refreservation property
3266 reservation property
3267 secondarycache property
3268 setuid property
3269 sharenfs property
3270 sharesmb property
3271 snapdir property
3272 snapshot_limit property
3273 utf8only property
3274 version property
3275 volblocksize property
3276 volsize property
3277 vscan property
3278 xattr property
3279 zoned property
3280 .Ed
3281 .It Xo
3282 .Nm
3283 .Cm allow
3284 .Fl c
3285 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
3286 .Ar setname Oc Ns ...
3287 .Ar filesystem Ns | Ns Ar volume
3288 .Xc
3289 Sets
3290 .Qq create time
3291 permissions.
3292 These permissions are granted
3293 .Pq locally
3294 to the creator of any newly-created descendent file system.
3295 .It Xo
3296 .Nm
3297 .Cm allow
3298 .Fl s No @ Ns Ar setname
3299 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
3300 .Ar setname Oc Ns ...
3301 .Ar filesystem Ns | Ns Ar volume
3302 .Xc
3303 Defines or adds permissions to a permission set.
3304 The set can be used by other
3305 .Nm zfs Cm allow
3306 commands for the specified file system and its descendents.
3307 Sets are evaluated dynamically, so changes to a set are immediately reflected.
3308 Permission sets follow the same naming restrictions as ZFS file systems, but the
3309 name must begin with
3310 .Sy @ ,
3311 and can be no more than 64 characters long.
3312 .It Xo
3313 .Nm
3314 .Cm unallow
3315 .Op Fl dglru
3316 .Ar user Ns | Ns Ar group Ns Oo , Ns Ar user Ns | Ns Ar group Oc Ns ...
3317 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
3318 .Ar setname Oc Ns ... Oc
3319 .Ar filesystem Ns | Ns Ar volume
3320 .Xc
3321 .It Xo
3322 .Nm
3323 .Cm unallow
3324 .Op Fl dlr
3325 .Fl e Ns | Ns Sy everyone
3326 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
3327 .Ar setname Oc Ns ... Oc
3328 .Ar filesystem Ns | Ns Ar volume
3329 .Xc
3330 .It Xo
3331 .Nm
3332 .Cm unallow
3333 .Op Fl r
3334 .Fl c
3335 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
3336 .Ar setname Oc Ns ... Oc
3337 .Ar filesystem Ns | Ns Ar volume
3338 .Xc
3339 Removes permissions that were granted with the
3340 .Nm zfs Cm allow
3341 command.
3342 No permissions are explicitly denied, so other permissions granted are still in
3343 effect.
3344 For example, if the permission is granted by an ancestor.
3345 If no permissions are specified, then all permissions for the specified
3346 .Ar user ,
3347 .Ar group ,
3348 or
3349 .Sy everyone
3350 are removed.
3351 Specifying
3352 .Sy everyone
3353 .Po or using the
3354 .Fl e
3355 option
3356 .Pc
3357 only removes the permissions that were granted to everyone, not all permissions
3358 for every user and group.
3359 See the
3360 .Nm zfs Cm allow
3361 command for a description of the
3362 .Fl ldugec
3363 options.
3364 .Bl -tag -width "-r"
3365 .It Fl r
3366 Recursively remove the permissions from this file system and all descendents.
3367 .El
3368 .It Xo
3369 .Nm
3370 .Cm unallow
3371 .Op Fl r
3372 .Fl s No @ Ns Ar setname
3373 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
3374 .Ar setname Oc Ns ... Oc
3375 .Ar filesystem Ns | Ns Ar volume
3376 .Xc
3377 Removes permissions from a permission set.
3378 If no permissions are specified, then all permissions are removed, thus removing
3379 the set entirely.
3380 .It Xo
3381 .Nm
3382 .Cm hold
3383 .Op Fl r
3384 .Ar tag Ar snapshot Ns ...
3385 .Xc
3386 Adds a single reference, named with the
3387 .Ar tag
3388 argument, to the specified snapshot or snapshots.
3389 Each snapshot has its own tag namespace, and tags must be unique within that
3390 space.
3391 .Pp
3392 If a hold exists on a snapshot, attempts to destroy that snapshot by using the
3393 .Nm zfs Cm destroy
3394 command return
3395 .Er EBUSY .
3396 .Bl -tag -width "-r"
3397 .It Fl r
3398 Specifies that a hold with the given tag is applied recursively to the snapshots
3399 of all descendent file systems.
3400 .El
3401 .It Xo
3402 .Nm
3403 .Cm holds
3404 .Op Fl r
3405 .Ar snapshot Ns ...
3406 .Xc
3407 Lists all existing user references for the given snapshot or snapshots.
3408 .Bl -tag -width "-r"
3409 .It Fl r
3410 Lists the holds that are set on the named descendent snapshots, in addition to
3411 listing the holds on the named snapshot.
3412 .El
3413 .It Xo
3414 .Nm
3415 .Cm release
3416 .Op Fl r
3417 .Ar tag Ar snapshot Ns ...
3418 .Xc
3419 Removes a single reference, named with the
3420 .Ar tag
3421 argument, from the specified snapshot or snapshots.
3422 The tag must already exist for each snapshot.
3423 If a hold exists on a snapshot, attempts to destroy that snapshot by using the
3424 .Nm zfs Cm destroy
3425 command return
3426 .Er EBUSY .
3427 .Bl -tag -width "-r"
3428 .It Fl r
3429 Recursively releases a hold with the given tag on the snapshots of all
3430 descendent file systems.
3431 .El
3432 .It Xo
3433 .Nm
3434 .Cm diff
3435 .Op Fl FHt
3436 .Ar snapshot Ar snapshot Ns | Ns Ar filesystem
3437 .Xc
3438 Display the difference between a snapshot of a given filesystem and another
3439 snapshot of that filesystem from a later time or the current contents of the
3440 filesystem.
3441 The first column is a character indicating the type of change, the other columns
3442 indicate pathname, new pathname
3443 .Pq in case of rename ,
3444 change in link count, and optionally file type and/or change time.
3445 The types of change are:
3446 .Bd -literal
3447 - The path has been removed
3448 + The path has been created
3449 M The path has been modified
3450 R The path has been renamed
3451 .Ed
3452 .Bl -tag -width "-F"
3453 .It Fl F
3454 Display an indication of the type of file, in a manner similar to the
3455 .Fl
3456 option of
3457 .Xr ls 1 .
3458 .Bd -literal
3459 B Block device
3460 C Character device
3461 / Directory
3462 > Door
3463 | Named pipe
3464 @ Symbolic link
3465 P Event port
3466 = Socket
3467 F Regular file
3468 .Ed
3469 .It Fl H
3470 Give more parsable tab-separated output, without header lines and without
3471 arrows.
3472 .It Fl t
3473 Display the path's inode change time as the first column of output.
3474 .El
3475 .It Xo
3476 .Nm
3477 .Cm program
3478 .Op Fl n
3479 .Op Fl t Ar timeout
3480 .Op Fl m Ar memory_limit
3481 .Ar pool script
3482 .Op Ar arg1 No ...
3483 .Xc
3484 Executes
3485 .Ar script
3486 as a ZFS channel program on
3487 .Ar pool .
3488 The ZFS channel
3489 program interface allows ZFS administrative operations to be run
3490 programmatically via a Lua script.
3491 The entire script is executed atomically, with no other administrative
3492 operations taking effect concurrently.
3493 A library of ZFS calls is made available to channel program scripts.
3494 Channel programs may only be run with root privileges.
3495 .sp
3496 For full documentation of the ZFS channel program interface, see the manual
3497 page for
3498 .Bl -tag -width ""
3499 .It Fl n
3500 Executes a read-only channel program, which runs faster.
3501 The program cannot change on-disk state by calling functions from
3502 the zfs.sync submodule.
3503 The program can be used to gather information such as properties and
3504 determining if changes would succeed (zfs.check.*).
3505 Without this flag, all pending changes must be synced to disk before
3506 a channel program can complete.
3507 .It Fl t Ar timeout
3508 Execution time limit, in milliseconds.
3509 If a channel program executes for longer than the provided timeout, it will
3510 be stopped and an error will be returned.
3511 The default timeout is 1000 ms, and can be set to a maximum of 10000 ms.
3512 .It Fl m Ar memory-limit
3513 Memory limit, in bytes.
3514 If a channel program attempts to allocate more memory than the given limit,
3515 it will be stopped and an error returned.
3516 The default memory limit is 10 MB, and can be set to a maximum of 100 MB.
3517 .sp
3518 All remaining argument strings are passed directly to the channel program as
3519 arguments.
3520 See
3521 .Xr zfs-program 1M
3522 for more information.
3523 .El
3524 .El
3525 .Sh EXIT STATUS
3526 The
3527 .Nm
3528 utility exits 0 on success, 1 if an error occurs, and 2 if invalid command line
3529 options were specified.
3530 .Sh EXAMPLES
3531 .Bl -tag -width ""
3532 .It Sy Example 1 No Creating a ZFS File System Hierarchy
3533 The following commands create a file system named
3534 .Em pool/home
3535 and a file system named
3536 .Em pool/home/bob .
3537 The mount point
3538 .Pa /export/home
3539 is set for the parent file system, and is automatically inherited by the child
3540 file system.
3541 .Bd -literal
3542 # zfs create pool/home
3543 # zfs set mountpoint=/export/home pool/home
3544 # zfs create pool/home/bob
3545 .Ed
3546 .It Sy Example 2 No Creating a ZFS Snapshot
3547 The following command creates a snapshot named
3548 .Sy yesterday .
3549 This snapshot is mounted on demand in the
3550 .Pa .zfs/snapshot
3551 directory at the root of the
3552 .Em pool/home/bob
3553 file system.
3554 .Bd -literal
3555 # zfs snapshot pool/home/bob@yesterday
3556 .Ed
3557 .It Sy Example 3 No Creating and Destroying Multiple Snapshots
3558 The following command creates snapshots named
3559 .Sy yesterday
3560 of
3561 .Em pool/home
3562 and all of its descendent file systems.
3563 Each snapshot is mounted on demand in the
3564 .Pa .zfs/snapshot
3565 directory at the root of its file system.
3566 The second command destroys the newly created snapshots.
3567 .Bd -literal
3568 # zfs snapshot -r pool/home@yesterday
3569 # zfs destroy -r pool/home@yesterday
3570 .Ed
3571 .It Sy Example 4 No Disabling and Enabling File System Compression
3572 The following command disables the
3573 .Sy compression
3574 property for all file systems under
3575 .Em pool/home .
3576 The next command explicitly enables
3577 .Sy compression
3578 for
3579 .Em pool/home/anne .
3580 .Bd -literal
3581 # zfs set compression=off pool/home
3582 # zfs set compression=on pool/home/anne
3583 .Ed
3584 .It Sy Example 5 No Listing ZFS Datasets
3585 The following command lists all active file systems and volumes in the system.
3586 Snapshots are displayed if the
3587 .Sy listsnaps
3588 property is
3589 .Sy on .
3590 The default is
3591 .Sy off .
3592 See
3593 .Xr zpool 1M
3594 for more information on pool properties.
3595 .Bd -literal
3596 # zfs list
3597 NAME USED AVAIL REFER MOUNTPOINT
3598 pool 450K 457G 18K /pool
3599 pool/home 315K 457G 21K /export/home
3600 pool/home/anne 18K 457G 18K /export/home/anne
3601 pool/home/bob 276K 457G 276K /export/home/bob
3602 .Ed
3603 .It Sy Example 6 No Setting a Quota on a ZFS File System
3604 The following command sets a quota of 50 Gbytes for
3605 .Em pool/home/bob .
3606 .Bd -literal
3607 # zfs set quota=50G pool/home/bob
3608 .Ed
3609 .It Sy Example 7 No Listing ZFS Properties
3610 The following command lists all properties for
3611 .Em pool/home/bob .
3612 .Bd -literal
3613 # zfs get all pool/home/bob
3614 NAME PROPERTY VALUE SOURCE
3615 pool/home/bob type filesystem -
3616 pool/home/bob creation Tue Jul 21 15:53 2009 -
3617 pool/home/bob used 21K -
3618 pool/home/bob available 20.0G -
3619 pool/home/bob referenced 21K -
3620 pool/home/bob compressratio 1.00x -
3621 pool/home/bob mounted yes -
3622 pool/home/bob quota 20G local
3623 pool/home/bob reservation none default
3624 pool/home/bob recordsize 128K default
3625 pool/home/bob mountpoint /pool/home/bob default
3626 pool/home/bob sharenfs off default
3627 pool/home/bob checksum on default
3628 pool/home/bob compression on local
3629 pool/home/bob atime on default
3630 pool/home/bob devices on default
3631 pool/home/bob exec on default
3632 pool/home/bob setuid on default
3633 pool/home/bob readonly off default
3634 pool/home/bob zoned off default
3635 pool/home/bob snapdir hidden default
3636 pool/home/bob aclmode discard default
3637 pool/home/bob aclinherit restricted default
3638 pool/home/bob canmount on default
3639 pool/home/bob xattr on default
3640 pool/home/bob copies 1 default
3641 pool/home/bob version 4 -
3642 pool/home/bob utf8only off -
3643 pool/home/bob normalization none -
3644 pool/home/bob casesensitivity sensitive -
3645 pool/home/bob vscan off default
3646 pool/home/bob nbmand off default
3647 pool/home/bob sharesmb off default
3648 pool/home/bob refquota none default
3649 pool/home/bob refreservation none default
3650 pool/home/bob primarycache all default
3651 pool/home/bob secondarycache all default
3652 pool/home/bob usedbysnapshots 0 -
3653 pool/home/bob usedbydataset 21K -
3654 pool/home/bob usedbychildren 0 -
3655 pool/home/bob usedbyrefreservation 0 -
3656 .Ed
3657 .Pp
3658 The following command gets a single property value.
3659 .Bd -literal
3660 # zfs get -H -o value compression pool/home/bob
3661 on
3662 .Ed
3663 The following command lists all properties with local settings for
3664 .Em pool/home/bob .
3665 .Bd -literal
3666 # zfs get -r -s local -o name,property,value all pool/home/bob
3667 NAME PROPERTY VALUE
3668 pool/home/bob quota 20G
3669 pool/home/bob compression on
3670 .Ed
3671 .It Sy Example 8 No Rolling Back a ZFS File System
3672 The following command reverts the contents of
3673 .Em pool/home/anne
3674 to the snapshot named
3675 .Sy yesterday ,
3676 deleting all intermediate snapshots.
3677 .Bd -literal
3678 # zfs rollback -r pool/home/anne@yesterday
3679 .Ed
3680 .It Sy Example 9 No Creating a ZFS Clone
3681 The following command creates a writable file system whose initial contents are
3682 the same as
3683 .Em pool/home/bob@yesterday .
3684 .Bd -literal
3685 # zfs clone pool/home/bob@yesterday pool/clone
3686 .Ed
3687 .It Sy Example 10 No Promoting a ZFS Clone
3688 The following commands illustrate how to test out changes to a file system, and
3689 then replace the original file system with the changed one, using clones, clone
3690 promotion, and renaming:
3691 .Bd -literal
3692 # zfs create pool/project/production
3693 populate /pool/project/production with data
3694 # zfs snapshot pool/project/production@today
3695 # zfs clone pool/project/production@today pool/project/beta
3696 make changes to /pool/project/beta and test them
3697 # zfs promote pool/project/beta
3698 # zfs rename pool/project/production pool/project/legacy
3699 # zfs rename pool/project/beta pool/project/production
3700 once the legacy version is no longer needed, it can be destroyed
3701 # zfs destroy pool/project/legacy
3702 .Ed
3703 .It Sy Example 11 No Inheriting ZFS Properties
3704 The following command causes
3705 .Em pool/home/bob
3706 and
3707 .Em pool/home/anne
3708 to inherit the
3709 .Sy checksum
3710 property from their parent.
3711 .Bd -literal
3712 # zfs inherit checksum pool/home/bob pool/home/anne
3713 .Ed
3714 .It Sy Example 12 No Remotely Replicating ZFS Data
3715 The following commands send a full stream and then an incremental stream to a
3716 remote machine, restoring them into
3717 .Em poolB/received/fs@a
3718 and
3719 .Em poolB/received/fs@b ,
3720 respectively.
3721 .Em poolB
3722 must contain the file system
3723 .Em poolB/received ,
3724 and must not initially contain
3725 .Em poolB/received/fs .
3726 .Bd -literal
3727 # zfs send pool/fs@a | \e
3728 ssh host zfs receive poolB/received/fs@a
3729 # zfs send -i a pool/fs@b | \e
3730 ssh host zfs receive poolB/received/fs
3731 .Ed
3732 .It Sy Example 13 No Using the zfs receive -d Option
3733 The following command sends a full stream of
3734 .Em poolA/fsA/fsB@snap
3735 to a remote machine, receiving it into
3736 .Em poolB/received/fsA/fsB@snap .
3737 The
3738 .Em fsA/fsB@snap
3739 portion of the received snapshot's name is determined from the name of the sent
3740 snapshot.
3741 .Em poolB
3742 must contain the file system
3743 .Em poolB/received .
3744 If
3745 .Em poolB/received/fsA
3746 does not exist, it is created as an empty file system.
3747 .Bd -literal
3748 # zfs send poolA/fsA/fsB@snap | \e
3749 ssh host zfs receive -d poolB/received
3750 .Ed
3751 .It Sy Example 14 No Setting User Properties
3752 The following example sets the user-defined
3753 .Sy com.example:department
3754 property for a dataset.
3755 .Bd -literal
3756 # zfs set com.example:department=12345 tank/accounting
3757 .Ed
3758 .It Sy Example 15 No Performing a Rolling Snapshot
3759 The following example shows how to maintain a history of snapshots with a
3760 consistent naming scheme.
3761 To keep a week's worth of snapshots, the user destroys the oldest snapshot,
3762 renames the remaining snapshots, and then creates a new snapshot, as follows:
3763 .Bd -literal
3764 # zfs destroy -r pool/users@7daysago
3765 # zfs rename -r pool/users@6daysago @7daysago
3766 # zfs rename -r pool/users@5daysago @6daysago
3767 # zfs rename -r pool/users@yesterday @5daysago
3768 # zfs rename -r pool/users@yesterday @4daysago
3769 # zfs rename -r pool/users@yesterday @3daysago
3770 # zfs rename -r pool/users@yesterday @2daysago
3771 # zfs rename -r pool/users@today @yesterday
3772 # zfs snapshot -r pool/users@today
3773 .Ed
3774 .It Sy Example 16 No Setting sharenfs Property Options on a ZFS File System
3775 The following commands show how to set
3776 .Sy sharenfs
3777 property options to enable
3778 .Sy rw
3779 access for a set of
3780 .Sy IP
3781 addresses and to enable root access for system
3782 .Sy neo
3783 on the
3784 .Em tank/home
3785 file system.
3786 .Bd -literal
3787 # zfs set sharenfs='rw=@123.123.0.0/16,root=neo' tank/home
3788 .Ed
3789 .Pp
3790 If you are using
3791 .Sy DNS
3792 for host name resolution, specify the fully qualified hostname.
3793 .It Sy Example 17 No Delegating ZFS Administration Permissions on a ZFS Dataset
3794 The following example shows how to set permissions so that user
3795 .Sy cindys
3796 can create, destroy, mount, and take snapshots on
3797 .Em tank/cindys .
3798 The permissions on
3799 .Em tank/cindys
3800 are also displayed.
3801 .Bd -literal
3802 # zfs allow cindys create,destroy,mount,snapshot tank/cindys
3803 # zfs allow tank/cindys
3804 ---- Permissions on tank/cindys --------------------------------------
3805 Local+Descendent permissions:
3806 user cindys create,destroy,mount,snapshot
3807 .Ed
3808 .Pp
3809 Because the
3810 .Em tank/cindys
3811 mount point permission is set to 755 by default, user
3812 .Sy cindys
3813 will be unable to mount file systems under
3814 .Em tank/cindys .
3815 Add an ACE similar to the following syntax to provide mount point access:
3816 .Bd -literal
3817 # chmod A+user:cindys:add_subdirectory:allow /tank/cindys
3818 .Ed
3819 .It Sy Example 18 No Delegating Create Time Permissions on a ZFS Dataset
3820 The following example shows how to grant anyone in the group
3821 .Sy staff
3822 to create file systems in
3823 .Em tank/users .
3824 This syntax also allows staff members to destroy their own file systems, but not
3825 destroy anyone else's file system.
3826 The permissions on
3827 .Em tank/users
3828 are also displayed.
3829 .Bd -literal
3830 # zfs allow staff create,mount tank/users
3831 # zfs allow -c destroy tank/users
3832 # zfs allow tank/users
3833 ---- Permissions on tank/users ---------------------------------------
3834 Permission sets:
3835 destroy
3836 Local+Descendent permissions:
3837 group staff create,mount
3838 .Ed
3839 .It Sy Example 19 No Defining and Granting a Permission Set on a ZFS Dataset
3840 The following example shows how to define and grant a permission set on the
3841 .Em tank/users
3842 file system.
3843 The permissions on
3844 .Em tank/users
3845 are also displayed.
3846 .Bd -literal
3847 # zfs allow -s @pset create,destroy,snapshot,mount tank/users
3848 # zfs allow staff @pset tank/users
3849 # zfs allow tank/users
3850 ---- Permissions on tank/users ---------------------------------------
3851 Permission sets:
3852 @pset create,destroy,mount,snapshot
3853 Local+Descendent permissions:
3854 group staff @pset
3855 .Ed
3856 .It Sy Example 20 No Delegating Property Permissions on a ZFS Dataset
3857 The following example shows to grant the ability to set quotas and reservations
3858 on the
3859 .Em users/home
3860 file system.
3861 The permissions on
3862 .Em users/home
3863 are also displayed.
3864 .Bd -literal
3865 # zfs allow cindys quota,reservation users/home
3866 # zfs allow users/home
3867 ---- Permissions on users/home ---------------------------------------
3868 Local+Descendent permissions:
3869 user cindys quota,reservation
3870 cindys% zfs set quota=10G users/home/marks
3871 cindys% zfs get quota users/home/marks
3872 NAME PROPERTY VALUE SOURCE
3873 users/home/marks quota 10G local
3874 .Ed
3875 .It Sy Example 21 No Removing ZFS Delegated Permissions on a ZFS Dataset
3876 The following example shows how to remove the snapshot permission from the
3877 .Sy staff
3878 group on the
3879 .Em tank/users
3880 file system.
3881 The permissions on
3882 .Em tank/users
3883 are also displayed.
3884 .Bd -literal
3885 # zfs unallow staff snapshot tank/users
3886 # zfs allow tank/users
3887 ---- Permissions on tank/users ---------------------------------------
3888 Permission sets:
3889 @pset create,destroy,mount,snapshot
3890 Local+Descendent permissions:
3891 group staff @pset
3892 .Ed
3893 .It Sy Example 22 No Showing the differences between a snapshot and a ZFS Dataset
3894 The following example shows how to see what has changed between a prior
3895 snapshot of a ZFS dataset and its current state.
3896 The
3897 .Fl F
3898 option is used to indicate type information for the files affected.
3899 .Bd -literal
3900 # zfs diff -F tank/test@before tank/test
3901 M / /tank/test/
3902 M F /tank/test/linked (+1)
3903 R F /tank/test/oldname -> /tank/test/newname
3904 - F /tank/test/deleted
3905 + F /tank/test/created
3906 M F /tank/test/modified
3907 .Ed
3908 .El
3909 .Sh INTERFACE STABILITY
3910 .Sy Committed .
3911 .Sh SEE ALSO
3912 .Xr gzip 1 ,
3913 .Xr ssh 1 ,
3914 .Xr mount 1M ,
3915 .Xr share 1M ,
3916 .Xr sharemgr 1M ,
3917 .Xr unshare 1M ,
3918 .Xr zonecfg 1M ,
3919 .Xr zpool 1M ,
3920 .Xr chmod 2 ,
3921 .Xr stat 2 ,
3922 .Xr write 2 ,
3923 .Xr fsync 3C ,
3924 .Xr dfstab 4 ,
3925 .Xr acl 5 ,
3926 .Xr attributes 5