NAME

SYNOPSIS

DESCRIPTION

pool/{filesystem,volume,snapshot}

 

 

file system

A ZFS dataset of type filesystem can be mounted within the standard system namespace and behaves like other file systems. While ZFS file systems are designed to be POSIX compliant, known issues exist that prevent compliance in some cases. Applications that depend on standards conformance might fail due to non-standard behavior when checking file system free space.

 

 

volume

A logical volume exported as a raw or block device. This type of dataset should only be used under special circumstances. File systems are typically used in most environments.

 

 

snapshot

A read-only version of a file system or volume at a given point in time. It is specified as filesystem@name or volume@name.

ZFS File System Hierarchy

Snapshots

Clones

Mount Points

Zones

Native Properties

 

 

available

The amount of space available to the dataset and all its children, assuming that there is no other activity in the pool. Because space is shared within a pool, availability can be limited by any number of factors, including physical pool size, quotas, reservations, or other datasets within the pool.

This property can also be referred to by its shortened column name, avail.

 

 

compressratio

For non-snapshots, the compression ratio achieved for the used space of this dataset, expressed as a multiplier. The used property includes descendant datasets, and, for clones, does not include the space shared with the origin snapshot. For snapshots, the compressratio is the same as the refcompressratio property. Compression can be turned on by running: zfs set compression=on dataset. The default value is off.

 

 

createtxg

The transaction group (txg) in which the dataset was created. Bookmarks have the same createtxg as the snapshot they are initially tied to. This property is suitable for ordering a list of snapshots, e.g. for incremental send and receive.

 

 

creation

The time this dataset was created.

 

 

clones

For snapshots, this property is a comma-separated list of filesystems or volumes which are clones of this snapshot. The clones' origin property is this snapshot. If the clones property is not empty, then this snapshot can not be destroyed (even with the -r or -f options).

 

 

defer_destroy

This property is on if the snapshot has been marked for deferred destroy by using the zfs destroy -d command. Otherwise, the property is off.

 

 

filesystem_count

The total number of filesystems and volumes that exist under this location in the dataset tree. This value is only available when a filesystem_limit has been set somewhere in the tree under which the dataset resides.

 

 

guid

The 64 bit GUID of this dataset or bookmark which does not change over its entire lifetime. When a snapshot is sent to another pool, the received snapshot has the same GUID. Thus, the guid is suitable to identify a snapshot across pools.

 

 

logicalreferenced

The amount of space that is “logically” accessible by this dataset. See the referenced property. The logical space ignores the effect of the compression and copies properties, giving a quantity closer to the amount of data that applications see. However, it does include space consumed by metadata.

This property can also be referred to by its shortened column name, lrefer.

 

 

logicalused

The amount of space that is “logically” consumed by this dataset and all its descendents. See the used property. The logical space ignores the effect of the compression and copies properties, giving a quantity closer to the amount of data that applications see. However, it does include space consumed by metadata.

This property can also be referred to by its shortened column name, lused.

 

 

mounted

For file systems, indicates whether the file system is currently mounted. This property can be either yes or no.

 

 

origin

For cloned file systems or volumes, the snapshot from which the clone was created. See also the clones property.

 

 

receive_resume_token

For filesystems or volumes which have saved partially-completed state from zfs receive -s, this opaque token can be provided to zfs send -t to resume and complete the zfs receive.

 

 

referenced

The amount of data that is accessible by this dataset, which may or may not be shared with other datasets in the pool. When a snapshot or clone is created, it initially references the same amount of space as the file system or snapshot it was created from, since its contents are identical.

This property can also be referred to by its shortened column name, refer.

 

 

refcompressratio

The compression ratio achieved for the referenced space of this dataset, expressed as a multiplier. See also the compressratio property.

 

 

snapshot_count

The total number of snapshots that exist under this location in the dataset tree. This value is only available when a snapshot_limit has been set somewhere in the tree under which the dataset resides.

 

 

type

The type of dataset: filesystem, volume, or snapshot.

 

 

used

The amount of space consumed by this dataset and all its descendents. This is the value that is checked against this dataset's quota and reservation. The space used does not include this dataset's reservation, but does take into account the reservations of any descendent datasets. The amount of space that a dataset consumes from its parent, as well as the amount of space that is freed if this dataset is recursively destroyed, is the greater of its space used and its reservation.

The used space of a snapshot (see the Snapshots section) is space that is referenced exclusively by this snapshot. If this snapshot is destroyed, the amount of used space will be freed. Space that is shared by multiple snapshots isn't accounted for in this metric. When a snapshot is destroyed, space that was previously shared with this snapshot can become unique to snapshots adjacent to it, thus changing the used space of those snapshots. The used space of the latest snapshot can also be affected by changes in the file system. Note that the used space of a snapshot is a subset of the written space of the snapshot.

The amount of space used, available, or referenced does not take into account pending changes. Pending changes are generally accounted for within a few seconds. Committing a change to a disk using fsync(3C) or O_SYNC does not necessarily guarantee that the space usage information is updated immediately.

 

 

usedby*

The usedby* properties decompose the used properties into the various reasons that space is used. Specifically, used = usedbychildren + usedbydataset + usedbyrefreservation + usedbysnapshots. These properties are only available for datasets created on zpool “version 13” pools.

 

 

usedbychildren

The amount of space used by children of this dataset, which would be freed if all the dataset's children were destroyed.

 

 

usedbydataset

The amount of space used by this dataset itself, which would be freed if the dataset were destroyed (after first removing any refreservation and destroying any necessary snapshots or descendents).

 

 

usedbyrefreservation

The amount of space used by a refreservation set on this dataset, which would be freed if the refreservation was removed.

 

 

usedbysnapshots

The amount of space consumed by snapshots of this dataset. In particular, it is the amount of space that would be freed if all of this dataset's snapshots were destroyed. Note that this is not simply the sum of the snapshots' used properties because space can be shared by multiple snapshots.

 

 

userused@user

The amount of space consumed by the specified user in this dataset. Space is charged to the owner of each file, as displayed by ls -l. The amount of space charged is displayed by du and ls -s. See the zfs userspace subcommand for more information.

Unprivileged users can access only their own space usage. The root user, or a user who has been granted the userused privilege with zfs allow, can access everyone's usage.

The userused@... properties are not displayed by zfs get all. The user's name must be appended after the @ symbol, using one of the following forms:

• POSIX name (for example, joe)
• POSIX numeric ID (for example, 789)
• SID name (for example, joe.smith@mydomain)
• SID numeric ID (for example, S-1-123-456-789)

 

 

userrefs

This property is set to the number of user holds on this snapshot. User holds are set by using the zfs hold command.

 

 

groupused@group

The amount of space consumed by the specified group in this dataset. Space is charged to the group of each file, as displayed by ls -l. See the userused@user property for more information.

Unprivileged users can only access their own groups' space usage. The root user, or a user who has been granted the groupused privilege with zfs allow, can access all groups' usage.

 

 

volblocksize

For volumes, specifies the block size of the volume. The blocksize cannot be changed once the volume has been written, so it should be set at volume creation time. The default blocksize for volumes is 8 Kbytes. Any power of 2 from 512 bytes to 128 Kbytes is valid.

This property can also be referred to by its shortened column name, volblock.

 

 

written

The amount of space referenced by this dataset, that was written since the previous snapshot (i.e. that is not referenced by the previous snapshot).

 

 

written@snapshot

The amount of referenced space written to this dataset since the specified snapshot. This is the space that is referenced by this dataset but was not referenced by the specified snapshot.

The snapshot may be specified as a short snapshot name (just the part after the @), in which case it will be interpreted as a snapshot in the same filesystem as this dataset. The snapshot may be a full snapshot name (filesystem@snapshot), which for clones may be a snapshot in the origin's filesystem (or the origin of the origin's filesystem, etc.)

 

 

aclinherit=discard|noallow|restricted|passthrough|passthrough-x

Controls how ACEs are inherited when files and directories are created.

 

 

discard

does not inherit any ACEs.

 

 

noallow

only inherits inheritable ACEs that specify “deny” permissions.

 

 

restricted

default, removes the write_acl and write_owner permissions when the ACE is inherited.

 

 

passthrough

inherits all inheritable ACEs without any modifications.

 

 

passthrough-x

same meaning as passthrough, except that the owner@, group@, and everyone@ ACEs inherit the execute permission only if the file creation mode also requests the execute bit.

When the property value is set to passthrough, files are created with a mode determined by the inheritable ACEs. If no inheritable ACEs exist that affect the mode, then the mode is set in accordance to the requested mode from the application.

 

 

aclmode=discard|groupmask|passthrough|restricted

Controls how an ACL is modified during chmod(2) and how inherited ACEs are modified by the file creation mode.

 

 

discard

default, deletes all ACEs except for those representing the mode of the file or directory requested by chmod(2).

 

 

groupmask

reduces permissions granted by all ALLOW entries found in the ACL such that they are no greater than the group permissions specified by the mode.

 

 

passthrough

indicates that no changes are made to the ACL other than creating or updating the necessary ACEs to represent the new mode of the file or directory.

 

 

restricted

causes the chmod(2) operation to return an error when used on any file or directory which has a non-trivial ACL, with entries in addition to those that represent the mode.

chmod(2) is required to change the set user ID, set group ID, or sticky bit on a file or directory, as they do not have equivalent ACEs. In order to use chmod(2) on a file or directory with a non-trivial ACL when aclmode is set to restricted, you must first remove all ACEs except for those that represent the current mode.

 

 

atime=on|off

Controls whether the access time for files is updated when they are read. Turning this property off avoids producing write traffic when reading files and can result in significant performance gains, though it might confuse mailers and other similar utilities. The default value is on.

 

 

canmount=on|off|noauto

If this property is set to off, the file system cannot be mounted, and is ignored by zfs mount -a. Setting this property to off is similar to setting the mountpoint property to none, except that the dataset still has a normal mountpoint property, which can be inherited. Setting this property to off allows datasets to be used solely as a mechanism to inherit properties. One example of setting canmount=off is to have two datasets with the same mountpoint, so that the children of both datasets appear in the same directory, but might have different inherited characteristics.

When set to noauto, a dataset can only be mounted and unmounted explicitly. The dataset is not mounted automatically when the dataset is created or imported, nor is it mounted by the zfs mount -a command or unmounted by the zfs unmount -a command.

This property is not inherited.

 

 

checksum=on|off|fletcher2|fletcher4|sha256|noparity|sha512|skein|edonr

Controls the checksum used to verify data integrity. The default value is on, which automatically selects an appropriate algorithm (currently, fletcher4, but this may change in future releases). The value off disables integrity checking on user data. The value noparity not only disables integrity but also disables maintaining parity for user data. This setting is used internally by a dump device residing on a RAID-Z pool and should not be used by any other dataset. Disabling checksums is NOT a recommended practice.

The sha512, skein, and edonr checksum algorithms require enabling the appropriate features on the pool. Please see zpool-features(5) for more information on these algorithms.

Changing this property affects only newly-written data.

 

 

compression=on|off|gzip|gzip-N|lz4|lzjb|zle

Controls the compression algorithm used for this dataset.

Setting compression to on indicates that the current default compression algorithm should be used. The default balances compression and decompression speed, with compression ratio and is expected to work well on a wide variety of workloads. Unlike all other settings for this property, on does not select a fixed compression type. As new compression algorithms are added to ZFS and enabled on a pool, the default compression algorithm may change. The current default compression algorithm is either lzjb or, if the lz4_compress feature is enabled, lz4.

The lz4 compression algorithm is a high-performance replacement for the lzjb algorithm. It features significantly faster compression and decompression, as well as a moderately higher compression ratio than lzjb, but can only be used on pools with the lz4_compress feature set to enabled. See zpool-features(5) for details on ZFS feature flags and the lz4_compress feature.

The lzjb compression algorithm is optimized for performance while providing decent data compression.

The gzip compression algorithm uses the same compression as the gzip(1) command. You can specify the gzip level by using the value gzip-N, where N is an integer from 1 (fastest) to 9 (best compression ratio). Currently, gzip is equivalent to gzip-6 (which is also the default for gzip(1)).

The zle compression algorithm compresses runs of zeros.

This property can also be referred to by its shortened column name compress. Changing this property affects only newly-written data.

 

 

copies=1|2|3

Controls the number of copies of data stored for this dataset. These copies are in addition to any redundancy provided by the pool, for example, mirroring or RAID-Z. The copies are stored on different disks, if possible. The space used by multiple copies is charged to the associated file and dataset, changing the used property and counting against quotas and reservations.

Changing this property only affects newly-written data. Therefore, set this property at file system creation time by using the -o copies=N option.

 

 

devices=on|off

Controls whether device nodes can be opened on this file system. The default value is on.

 

 

exec=on|off

Controls whether processes can be executed from within this file system. The default value is on.

 

 

filesystem_limit=count|none

Limits the number of filesystems and volumes that can exist under this point in the dataset tree. The limit is not enforced if the user is allowed to change the limit. Setting a filesystem_limit to on a descendent of a filesystem that already has a filesystem_limit does not override the ancestor's filesystem_limit, but rather imposes an additional limit. This feature must be enabled to be used (see zpool-features(5)).

 

 

mountpoint=path|none|legacy

Controls the mount point used for this file system. See the Mount Points section for more information on how this property is used.

When the mountpoint property is changed for a file system, the file system and any children that inherit the mount point are unmounted. If the new value is legacy, then they remain unmounted. Otherwise, they are automatically remounted in the new location if the property was previously legacy or none, or if they were mounted before the property was changed. In addition, any shared file systems are unshared and shared in the new location.

 

 

nbmand=on|off

Controls whether the file system should be mounted with nbmand (Non Blocking mandatory locks). This is used for SMB clients. Changes to this property only take effect when the file system is umounted and remounted. See mount(1M) for more information on nbmand mounts.

 

 

primarycache=all|none|metadata

Controls what is cached in the primary cache (ARC). If this property is set to all, then both user data and metadata is cached. If this property is set to none, then neither user data nor metadata is cached. If this property is set to metadata, then only metadata is cached. The default value is all.

 

 

quota=size|none

Limits the amount of space a dataset and its descendents can consume. This property enforces a hard limit on the amount of space used. This includes all space consumed by descendents, including file systems and snapshots. Setting a quota on a descendent of a dataset that already has a quota does not override the ancestor's quota, but rather imposes an additional limit.

Quotas cannot be set on volumes, as the volsize property acts as an implicit quota.

 

 

snapshot_limit=count|none

Limits the number of snapshots that can be created on a dataset and its descendents. Setting a snapshot_limit on a descendent of a dataset that already has a snapshot_limit does not override the ancestor's snapshot_limit, but rather imposes an additional limit. The limit is not enforced if the user is allowed to change the limit. For example, this means that recursive snapshots taken from the global zone are counted against each delegated dataset within a zone. This feature must be enabled to be used (see zpool-features(5)).

 

 

userquota@user=size|none

Limits the amount of space consumed by the specified user. User space consumption is identified by the userspace@user property.

Enforcement of user quotas may be delayed by several seconds. This delay means that a user might exceed their quota before the system notices that they are over quota and begins to refuse additional writes with the EDQUOT error message. See the zfs userspace subcommand for more information.

Unprivileged users can only access their own groups' space usage. The root user, or a user who has been granted the userquota privilege with zfs allow, can get and set everyone's quota.

This property is not available on volumes, on file systems before version 4, or on pools before version 15. The userquota@... properties are not displayed by zfs get all. The user's name must be appended after the @ symbol, using one of the following forms:

• POSIX name (for example, joe)
• POSIX numeric ID (for example, 789)
• SID name (for example, joe.smith@mydomain)
• SID numeric ID (for example, S-1-123-456-789)

 

 

groupquota@group=size|none

Limits the amount of space consumed by the specified group. Group space consumption is identified by the groupused@group property.

Unprivileged users can access only their own groups' space usage. The root user, or a user who has been granted the groupquota privilege with zfs allow, can get and set all groups' quotas.

 

 

readonly=on|off

Controls whether this dataset can be modified. The default value is off.

This property can also be referred to by its shortened column name, rdonly.

 

 

recordsize=size

Specifies a suggested block size for files in the file system. This property is designed solely for use with database workloads that access files in fixed-size records. ZFS automatically tunes block sizes according to internal algorithms optimized for typical access patterns.

For databases that create very large files but access them in small random chunks, these algorithms may be suboptimal. Specifying a recordsize greater than or equal to the record size of the database can result in significant performance gains. Use of this property for general purpose file systems is strongly discouraged, and may adversely affect performance.

The size specified must be a power of two greater than or equal to 512 and less than or equal to 128 Kbytes. If the large_blocks feature is enabled on the pool, the size may be up to 1 Mbyte. See zpool-features(5) for details on ZFS feature flags.

Changing the file system's recordsize affects only files created afterward; existing files are unaffected.

This property can also be referred to by its shortened column name, recsize.

 

 

redundant_metadata=all|most

Controls what types of metadata are stored redundantly. ZFS stores an extra copy of metadata, so that if a single block is corrupted, the amount of user data lost is limited. This extra copy is in addition to any redundancy provided at the pool level (e.g. by mirroring or RAID-Z), and is in addition to an extra copy specified by the copies property (up to a total of 3 copies). For example if the pool is mirrored, copies=2, and redundant_metadata=most, then ZFS stores 6 copies of most metadata, and 4 copies of data and some metadata.

When set to all, ZFS stores an extra copy of all metadata. If a single on-disk block is corrupt, at worst a single block of user data (which is recordsize bytes long) can be lost.

When set to most, ZFS stores an extra copy of most types of metadata. This can improve performance of random writes, because less metadata must be written. In practice, at worst about 100 blocks (of recordsize bytes each) of user data can be lost if a single on-disk block is corrupt. The exact behavior of which metadata blocks are stored redundantly may change in future releases.

The default value is all.

 

 

refquota=size|none

Limits the amount of space a dataset can consume. This property enforces a hard limit on the amount of space used. This hard limit does not include space used by descendents, including file systems and snapshots.

 

 

refreservation=size|none|auto

The minimum amount of space guaranteed to a dataset, not including its descendents. When the amount of space used is below this value, the dataset is treated as if it were taking up the amount of space specified by refreservation. The refreservation reservation is accounted for in the parent datasets' space used, and counts against the parent datasets' quotas and reservations.

If refreservation is set, a snapshot is only allowed if there is enough free pool space outside of this reservation to accommodate the current number of “referenced” bytes in the dataset.

If refreservation is set to auto, a volume is thick provisioned (or “not sparse”). refreservation=auto is only supported on volumes. See volsize in the Native Properties section for more information about sparse volumes.

This property can also be referred to by its shortened column name, refreserv.

 

 

reservation=size|none

The minimum amount of space guaranteed to a dataset and its descendants. When the amount of space used is below this value, the dataset is treated as if it were taking up the amount of space specified by its reservation. Reservations are accounted for in the parent datasets' space used, and count against the parent datasets' quotas and reservations.

This property can also be referred to by its shortened column name, reserv.

 

 

secondarycache=all|none|metadata

Controls what is cached in the secondary cache (L2ARC). If this property is set to all, then both user data and metadata is cached. If this property is set to none, then neither user data nor metadata is cached. If this property is set to metadata, then only metadata is cached. The default value is all.

 

 

setuid=on|off

Controls whether the setuid bit is respected for the file system. The default value is on.

 

 

sharesmb=on|off|opts

Controls whether the file system is shared via SMB, and what options are to be used. A file system with the sharesmb property set to off is managed through traditional tools such as sharemgr(1M). Otherwise, the file system is automatically shared and unshared with the zfs share and zfs unshare commands. If the property is set to on, the sharemgr(1M) command is invoked with no options. Otherwise, the sharemgr(1M) command is invoked with options equivalent to the contents of this property.

Because SMB shares requires a resource name, a unique resource name is constructed from the dataset name. The constructed name is a copy of the dataset name except that the characters in the dataset name, which would be invalid in the resource name, are replaced with underscore (_) characters. A pseudo property “name” is also supported that allows you to replace the data set name with a specified name. The specified name is then used to replace the prefix dataset in the case of inheritance. For example, if the dataset data/home/john is set to name=john, then data/home/john has a resource name of john. If a child dataset data/home/john/backups is shared, it has a resource name of john_backups.

When SMB shares are created, the SMB share name appears as an entry in the .zfs/shares directory. You can use the ls or chmod command to display the share-level ACLs on the entries in this directory.

When the sharesmb property is changed for a dataset, the dataset and any children inheriting the property are re-shared with the new options, only if the property was previously set to off, or if they were shared before the property was changed. If the new property is set to off, the file systems are unshared.

 

 

sharenfs=on|off|opts

Controls whether the file system is shared via NFS, and what options are to be used. A file system with a sharenfs property of off is managed through traditional tools such as share(1M), unshare(1M), and dfstab(4). Otherwise, the file system is automatically shared and unshared with the zfs share and zfs unshare commands. If the property is set to on, share(1M) command is invoked with no options. Otherwise, the share(1M) command is invoked with options equivalent to the contents of this property.

When the sharenfs property is changed for a dataset, the dataset and any children inheriting the property are re-shared with the new options, only if the property was previously off, or if they were shared before the property was changed. If the new property is off, the file systems are unshared.

 

 

logbias=latency|throughput

Provide a hint to ZFS about handling of synchronous requests in this dataset. If logbias is set to latency (the default), ZFS will use pool log devices (if configured) to handle the requests at low latency. If logbias is set to throughput, ZFS will not use configured pool log devices. ZFS will instead optimize synchronous operations for global pool throughput and efficient use of resources.

 

 

snapdir=hidden|visible

Controls whether the .zfs directory is hidden or visible in the root of the file system as discussed in the Snapshots section. The default value is hidden.

 

 

sync=standard|always|disabled

Controls the behavior of synchronous requests (e.g. fsync, O_DSYNC). standard is the POSIX specified behavior of ensuring all synchronous requests are written to stable storage and all devices are flushed to ensure data is not cached by device controllers (this is the default). always causes every file system transaction to be written and flushed before its system call returns. This has a large performance penalty. disabled disables synchronous requests. File system transactions are only committed to stable storage periodically. This option will give the highest performance. However, it is very dangerous as ZFS would be ignoring the synchronous transaction demands of applications such as databases or NFS. Administrators should only use this option when the risks are understood.

 

 

version=N|current

The on-disk version of this file system, which is independent of the pool version. This property can only be set to later supported versions. See the zfs upgrade command.

 

 

volsize=size

For volumes, specifies the logical size of the volume. By default, creating a volume establishes a reservation of equal size. For storage pools with a version number of 9 or higher, a refreservation is set instead. Any changes to volsize are reflected in an equivalent change to the reservation (or refreservation). The volsize can only be set to a multiple of volblocksize, and cannot be zero.

The reservation is kept equal to the volume's logical size to prevent unexpected behavior for consumers. Without the reservation, the volume could run out of space, resulting in undefined behavior or data corruption, depending on how the volume is used. These effects can also occur when the volume size is changed while it is in use (particularly when shrinking the size). Extreme care should be used when adjusting the volume size.

Though not recommended, a “sparse volume” (also known as “thin provisioned”) can be created by specifying the -s option to the zfs create -V command, or by changing the value of the refreservation property (or reservation property on pool version 8 or earlier) after the volume has been created. A “sparse volume” is a volume where the value of refreservation is less than the size of the volume plus the space required to store its metadata. Consequently, writes to a sparse volume can fail with ENOSPC when the pool is low on space. For a sparse volume, changes to volsize are not reflected in the refreservation. A volume that is not sparse is said to be “thick provisioned”. A sparse volume can become thick provisioned by setting refreservation to auto.

 

 

vscan=on|off

Controls whether regular files should be scanned for viruses when a file is opened and closed. In addition to enabling this property, the virus scan service must also be enabled for virus scanning to occur. The default value is off.

 

 

xattr=on|off

Controls whether extended attributes are enabled for this file system. The default value is on.

 

 

zoned=on|off

Controls whether the dataset is managed from a non-global zone. See the Zones section for more information. The default value is off.

 

 

casesensitivity=sensitive|insensitive|mixed

Indicates whether the file name matching algorithm used by the file system should be case-sensitive, case-insensitive, or allow a combination of both styles of matching. The default value for the casesensitivity property is sensitive. Traditionally, UNIX and POSIX file systems have case-sensitive file names.

The mixed value for the casesensitivity property indicates that the file system can support requests for both case-sensitive and case-insensitive matching behavior. Currently, case-insensitive matching behavior on a file system that supports mixed behavior is limited to the SMB server product. For more information about the mixed value behavior, see the "ZFS Administration Guide".

 

 

normalization=none|formC|formD|formKC|formKD

Indicates whether the file system should perform a unicode normalization of file names whenever two file names are compared, and which normalization algorithm should be used. File names are always stored unmodified, names are normalized as part of any comparison process. If this property is set to a legal value other than none, and the utf8only property was left unspecified, the utf8only property is automatically set to on. The default value of the normalization property is none. This property cannot be changed after the file system is created.

 

 

utf8only=on|off

Indicates whether the file system should reject file names that include characters that are not present in the UTF-8 character code set. If this property is explicitly set to off, the normalization property must either not be explicitly set or be set to none. The default value for the utf8only property is off. This property cannot be changed after the file system is created.

Temporary Mount Point Properties

    PROPERTY                MOUNT OPTION 
    devices                 devices/nodevices 
    exec                    exec/noexec 
    readonly                ro/rw 
    setuid                  setuid/nosetuid 
    xattr                   xattr/noxattr

User Properties

ZFS Volumes as Swap or Dump Devices

SUBCOMMANDS

 

 

zfs -?

Displays a help message.

 

 

zfs create [

-p

] [

-o property=value

]... filesystem

Creates a new ZFS file system. The file system is automatically mounted according to the mountpoint property inherited from the parent.

 

 

-o property=value

Sets the specified property as if the command zfs set property=value was invoked at the same time the dataset was created. Any editable ZFS property can also be set at creation time. Multiple -o options can be specified. An error results if the same property is specified in multiple -o options.

 

 

-p

Creates all the non-existing parent datasets. Datasets created in this manner are automatically mounted according to the mountpoint property inherited from their parent. Any property specified on the command line using the -o option is ignored. If the target filesystem already exists, the operation completes successfully.

 

 

zfs create [

-ps

] [

-b blocksize

] [

-o property=value

]... -V size volume

Creates a volume of the given size. The volume is exported as a block device in /dev/zvol/{dsk,rdsk}/path, where path is the name of the volume in the ZFS namespace. The size represents the logical size as exported by the device. By default, a reservation of equal size is created.

size is automatically rounded up to the nearest 128 Kbytes to ensure that the volume has an integral number of blocks regardless of blocksize.

 

 

-b blocksize

Equivalent to -o volblocksize=blocksize. If this option is specified in conjunction with -o volblocksize, the resulting behavior is undefined.

 

 

-o property=value

Sets the specified property as if the zfs set property=value command was invoked at the same time the dataset was created. Any editable ZFS property can also be set at creation time. Multiple -o options can be specified. An error results if the same property is specified in multiple -o options.

 

 

-p

Creates all the non-existing parent datasets. Datasets created in this manner are automatically mounted according to the mountpoint property inherited from their parent. Any property specified on the command line using the -o option is ignored. If the target filesystem already exists, the operation completes successfully.

 

 

-s

Creates a sparse volume with no reservation. See volsize in the Native Properties section for more information about sparse volumes.

 

 

zfs destroy [

-Rfnprv

] filesystem|volume

Destroys the given dataset. By default, the command unshares any file systems that are currently shared, unmounts any file systems that are currently mounted, and refuses to destroy a dataset that has active dependents (children or clones).

 

 

-R

Recursively destroy all dependents, including cloned file systems outside the target hierarchy.

 

 

-f

Force an unmount of any file systems using the unmount -f command. This option has no effect on non-file systems or unmounted file systems.

 

 

-n

Do a dry-run (“No-op”) deletion. No data will be deleted. This is useful in conjunction with the -v or -p flags to determine what data would be deleted.

 

 

-p

Print machine-parsable verbose information about the deleted data.

 

 

-r

Recursively destroy all children.

 

 

-v

Print verbose information about the deleted data.

Extreme care should be taken when applying either the -r or the -R options, as they can destroy large portions of a pool and cause unexpected behavior for mounted file systems in use.

 

 

zfs destroy [

-Rdnprv

] filesystem|volume@snap[

%snap[

,snap[

%snap

]

]

]...

The given snapshots are destroyed immediately if and only if the zfs destroy command without the -d option would have destroyed it. Such immediate destruction would occur, for example, if the snapshot had no clones and the user-initiated reference count were zero.

If a snapshot does not qualify for immediate destruction, it is marked for deferred deletion. In this state, it exists as a usable, visible snapshot until both of the preconditions listed above are met, at which point it is destroyed.

An inclusive range of snapshots may be specified by separating the first and last snapshots with a percent sign. The first and/or last snapshots may be left blank, in which case the filesystem's oldest or newest snapshot will be implied.

Multiple snapshots (or ranges of snapshots) of the same filesystem or volume may be specified in a comma-separated list of snapshots. Only the snapshot's short name (the part after the @) should be specified when using a range or comma-separated list to identify multiple snapshots.

 

 

-R

Recursively destroy all clones of these snapshots, including the clones, snapshots, and children. If this flag is specified, the -d flag will have no effect.

 

 

-d

Defer snapshot deletion.

 

 

-n

Do a dry-run (“No-op”) deletion. No data will be deleted. This is useful in conjunction with the -p or -v flags to determine what data would be deleted.

 

 

-p

Print machine-parsable verbose information about the deleted data.

 

 

-r

Destroy (or mark for deferred deletion) all snapshots with this name in descendent file systems.

 

 

-v

Print verbose information about the deleted data.

Extreme care should be taken when applying either the -r or the -R options, as they can destroy large portions of a pool and cause unexpected behavior for mounted file systems in use.

 

 

zfs destroy filesystem|volume#bookmark

The given bookmark is destroyed.

 

 

zfs snapshot [

-r

] [

-o property=value

]... filesystem@snapname|volume@snapname...

Creates snapshots with the given names. All previous modifications by successful system calls to the file system are part of the snapshots. Snapshots are taken atomically, so that all snapshots correspond to the same moment in time. See the Snapshots section for details.

 

 

-o property=value

Sets the specified property; see zfs create for details.

 

 

-r

Recursively create snapshots of all descendent datasets

 

 

zfs rollback [

-Rfr

] snapshot

Roll back the given dataset to a previous snapshot. When a dataset is rolled back, all data that has changed since the snapshot is discarded, and the dataset reverts to the state at the time of the snapshot. By default, the command refuses to roll back to a snapshot other than the most recent one. In order to do so, all intermediate snapshots and bookmarks must be destroyed by specifying the -r option.

The -rR options do not recursively destroy the child snapshots of a recursive snapshot. Only direct snapshots of the specified filesystem are destroyed by either of these options. To completely roll back a recursive snapshot, you must rollback the individual child snapshots.

 

 

-R

Destroy any more recent snapshots and bookmarks, as well as any clones of those snapshots.

 

 

-f

Used with the -R option to force an unmount of any clone file systems that are to be destroyed.

 

 

-r

Destroy any snapshots and bookmarks more recent than the one specified.

 

 

zfs clone [

-p

] [

-o property=value

]... snapshot filesystem|volume

Creates a clone of the given snapshot. See the Clones section for details. The target dataset can be located anywhere in the ZFS hierarchy, and is created as the same type as the original.

 

 

-o property=value

Sets the specified property; see zfs create for details.

 

 

-p

Creates all the non-existing parent datasets. Datasets created in this manner are automatically mounted according to the mountpoint property inherited from their parent. If the target filesystem or volume already exists, the operation completes successfully.

 

 

zfs promote clone-filesystem

Promotes a clone file system to no longer be dependent on its “origin” snapshot. This makes it possible to destroy the file system that the clone was created from. The clone parent-child dependency relationship is reversed, so that the origin file system becomes a clone of the specified file system.

The snapshot that was cloned, and any snapshots previous to this snapshot, are now owned by the promoted clone. The space they use moves from the origin file system to the promoted clone, so enough space must be available to accommodate these snapshots. No new space is consumed by this operation, but the space accounting is adjusted. The promoted clone must not have any conflicting snapshot names of its own. The rename subcommand can be used to rename any conflicting snapshots.

 

 

zfs rename [

-f

] filesystem|volume|snapshot filesystem|volume|snapshot

 

zfs rename [

-fp

] filesystem|volume filesystem|volume

Renames the given dataset. The new target can be located anywhere in the ZFS hierarchy, with the exception of snapshots. Snapshots can only be renamed within the parent file system or volume. When renaming a snapshot, the parent file system of the snapshot does not need to be specified as part of the second argument. Renamed file systems can inherit new mount points, in which case they are unmounted and remounted at the new mount point.

 

 

-f

Force unmount any filesystems that need to be unmounted in the process.

 

 

-p

Creates all the nonexistent parent datasets. Datasets created in this manner are automatically mounted according to the mountpoint property inherited from their parent.

 

 

zfs rename -r snapshot snapshot

Recursively rename the snapshots of all descendent datasets. Snapshots are the only dataset that can be renamed recursively.

 

 

zfs list [

-r|-d depth

] [

-Hp

] [

-o property[

,property

]...

] [

-s property

]... [

-S property

]... [

-t type[

,type

]...

] [

filesystem|volume|snapshot

]...

Lists the property information for the given datasets in tabular form. If specified, you can list property information by the absolute pathname or the relative pathname. By default, all file systems and volumes are displayed. Snapshots are displayed if the listsnaps property is on (the default is off). The following fields are displayed, name,used,available,referenced,mountpoint.

 

 

-H

Used for scripting mode. Do not print headers and separate fields by a single tab instead of arbitrary white space.

 

 

-S property

Same as the -s option, but sorts by property in descending order.

 

 

-d depth

Recursively display any children of the dataset, limiting the recursion to depth. A depth of 1 will display only the dataset and its direct children.

 

 

-o property

A comma-separated list of properties to display. The property must be:

• One of the properties described in the Native Properties section
• A user property
• The value name to display the dataset name
• The value space to display space usage properties on file systems and volumes. This is a shortcut for specifying -o name,avail,used,usedsnap,usedds,usedrefreserv,usedchild -t filesystem,volume syntax.

 

 

-p

Display numbers in parsable (exact) values.

 

 

-r

Recursively display any children of the dataset on the command line.

 

 

-s property

A property for sorting the output by column in ascending order based on the value of the property. The property must be one of the properties described in the Properties section, or the special value name to sort by the dataset name. Multiple properties can be specified at one time using multiple -s property options. Multiple -s options are evaluated from left to right in decreasing order of importance. The following is a list of sorting criteria:

• Numeric types sort in numeric order.
• String types sort in alphabetical order.
• Types inappropriate for a row sort that row to the literal bottom, regardless of the specified ordering.

If no sorting options are specified the existing behavior of zfs list is preserved.

 

 

-t type

A comma-separated list of types to display, where type is one of filesystem, snapshot, volume, bookmark, or all. For example, specifying -t snapshot displays only snapshots.

 

 

zfs set property=value [

property=value

]... filesystem|volume|snapshot...

Sets the property or list of properties to the given value(s) for each dataset. Only some properties can be edited. See the Properties section for more information on what properties can be set and acceptable values. Numeric values can be specified as exact values, or in a human-readable form with a suffix of B, K, M, G, T, P, E, Z (for bytes, kilobytes, megabytes, gigabytes, terabytes, petabytes, exabytes, or zettabytes, respectively). User properties can be set on snapshots. For more information, see the User Properties section.

 

 

zfs get [

-r|-d depth

] [

-Hp

] [

-o field[

,field

]...

] [

-s source[

,source

]...

] [

-t type[

,type

]...

] all | property[

,property

]... filesystem|volume|snapshot|bookmark...

Displays properties for the given datasets. If no datasets are specified, then the command displays properties for all datasets on the system. For each property, the following columns are displayed:

    name      Dataset name 
    property  Property name 
    value     Property value 
    source    Property source.  Can either be local, default, 
              temporary, inherited, or none (-).
    

All columns are displayed by default, though this can be controlled by using the -o option. This command takes a comma-separated list of properties as described in the Native Properties and User Properties sections.

The special value all can be used to display all properties that apply to the given dataset's type (filesystem, volume, snapshot, or bookmark).

 

 

-H

Display output in a form more easily parsed by scripts. Any headers are omitted, and fields are explicitly separated by a single tab instead of an arbitrary amount of space.

 

 

-d depth

Recursively display any children of the dataset, limiting the recursion to depth. A depth of 1 will display only the dataset and its direct children.

 

 

-o field

A comma-separated list of columns to display. name,property,value,source is the default value.

 

 

-p

Display numbers in parsable (exact) values.

 

 

-r

Recursively display properties for any children.

 

 

-s source

A comma-separated list of sources to display. Those properties coming from a source other than those in this list are ignored. Each source must be one of the following: local, default, inherited, temporary, and none. The default value is all sources.

 

 

-t type

A comma-separated list of types to display, where type is one of filesystem, snapshot, volume, bookmark, or all.

 

 

zfs inherit [

-rS

] property filesystem|volume|snapshot...

Clears the specified property, causing it to be inherited from an ancestor, restored to default if no ancestor has the property set, or with the -S option reverted to the received value if one exists. See the Properties section for a listing of default values, and details on which properties can be inherited.

 

 

-r

Recursively inherit the given property for all children.

 

 

-S

Revert the property to the received value if one exists; otherwise operate as if the -S option was not specified.

 

 

zfs remap filesystem|volume

Remap the indirect blocks in the given filesystem or volume so that they no longer reference blocks on previously removed vdevs and we can eventually shrink the size of the indirect mapping objects for the previously removed vdevs. Note that remapping all blocks might not be possible and that references from snapshots will still exist and cannot be remapped.

 

 

zfs upgrade

Displays a list of file systems that are not the most recent version.

 

 

zfs upgrade -v

Displays a list of currently supported file system versions.

 

 

zfs upgrade [

-r

] [

-V version

] -a | filesystem

Upgrades file systems to a new on-disk version. Once this is done, the file systems will no longer be accessible on systems running older versions of the software. zfs send streams generated from new snapshots of these file systems cannot be accessed on systems running older versions of the software.

In general, the file system version is independent of the pool version. See zpool(1M) for information on the zpool upgrade command.

In some cases, the file system version and the pool version are interrelated and the pool version must be upgraded before the file system version can be upgraded.

 

 

-V version

Upgrade to the specified version. If the -V flag is not specified, this command upgrades to the most recent version. This option can only be used to increase the version number, and only up to the most recent version supported by this software.

 

 

-a

Upgrade all file systems on all imported pools.

 

 

filesystem

Upgrade the specified file system.

 

 

-r

Upgrade the specified file system and all descendent file systems.

 

 

zfs userspace [

-Hinp

] [

-o field[

,field

]...

] [

-s field

]... [

-S field

]... [

-t type[

,type

]...

] filesystem|snapshot

Displays space consumed by, and quotas on, each user in the specified filesystem or snapshot. This corresponds to the userused@user and userquota@user properties.

 

 

-H

Do not print headers, use tab-delimited output.

 

 

-S field

Sort by this field in reverse order. See -s.

 

 

-i

Translate SID to POSIX ID. The POSIX ID may be ephemeral if no mapping exists. Normal POSIX interfaces (for example, stat(2), ls -l) perform this translation, so the -i option allows the output from zfs userspace to be compared directly with those utilities. However, -i may lead to confusion if some files were created by an SMB user before a SMB-to-POSIX name mapping was established. In such a case, some files will be owned by the SMB entity and some by the POSIX entity. However, the -i option will report that the POSIX entity has the total usage and quota for both.

 

 

-n

Print numeric ID instead of user/group name.

 

 

-o field[

,field

]...

Display only the specified fields from the following set: type, name, used, quota. The default is to display all fields.

 

 

-p

Use exact (parsable) numeric output.

 

 

-s field

Sort output by this field. The -s and -S flags may be specified multiple times to sort first by one field, then by another. The default is -s type -s name.

 

 

-t type[

,type

]...

Print only the specified types from the following set: all, posixuser, smbuser, posixgroup, smbgroup. The default is -t posixuser,smbuser. The default can be changed to include group types.

 

 

zfs groupspace [

-Hinp

] [

-o field[

,field

]...

] [

-s field

]... [

-S field

]... [

-t type[

,type

]...

] filesystem|snapshot

Displays space consumed by, and quotas on, each group in the specified filesystem or snapshot. This subcommand is identical to zfs userspace, except that the default types to display are -t posixgroup,smbgroup.

 

 

zfs mount

Displays all ZFS file systems currently mounted.

 

 

zfs mount [

-Ov

] [

-o options

] -a | filesystem

Mounts ZFS file systems.

 

 

-O

Perform an overlay mount. See mount(1M) for more information.

 

 

-a

Mount all available ZFS file systems. Invoked automatically as part of the boot process.

 

 

filesystem

Mount the specified filesystem.

 

 

-o options

An optional, comma-separated list of mount options to use temporarily for the duration of the mount. See the Temporary Mount Point Properties section for details.

 

 

-v

Report mount progress.

 

 

zfs unmount [

-f

] -a | filesystem|mountpoint

Unmounts currently mounted ZFS file systems.

 

 

-a

Unmount all available ZFS file systems. Invoked automatically as part of the shutdown process.

 

 

filesystem|mountpoint

Unmount the specified filesystem. The command can also be given a path to a ZFS file system mount point on the system.

 

 

-f

Forcefully unmount the file system, even if it is currently in use.

 

 

zfs share -a | filesystem

Shares available ZFS file systems.

 

 

-a

Share all available ZFS file systems. Invoked automatically as part of the boot process.

 

 

filesystem

Share the specified filesystem according to the sharenfs and sharesmb properties. File systems are shared when the sharenfs or sharesmb property is set.

 

 

zfs unshare -a | filesystem|mountpoint

Unshares currently shared ZFS file systems.

 

 

-a

Unshare all available ZFS file systems. Invoked automatically as part of the shutdown process.

 

 

filesystem|mountpoint

Unshare the specified filesystem. The command can also be given a path to a ZFS file system shared on the system.

 

 

zfs bookmark snapshot bookmark

Creates a bookmark of the given snapshot. Bookmarks mark the point in time when the snapshot was created, and can be used as the incremental source for a zfs send command.

This feature must be enabled to be used. See zpool-features(5) for details on ZFS feature flags and the bookmarks feature.

 

 

zfs send [

-DLPRcenpv

] [

[

-I|-i

] snapshot

] snapshot

Creates a stream representation of the second snapshot, which is written to standard output. The output can be redirected to a file or to a different system (for example, using ssh(1)). By default, a full stream is generated.

 

 

-D, --dedup

Generate a deduplicated stream. Blocks which would have been sent multiple times in the send stream will only be sent once. The receiving system must also support this feature to receive a deduplicated stream. This flag can be used regardless of the dataset's dedup property, but performance will be much better if the filesystem uses a dedup-capable checksum (for example, sha256).

 

 

-I snapshot

Generate a stream package that sends all intermediary snapshots from the first snapshot to the second snapshot. For example, -I @a fs@d is similar to -i @a fs@b; -i @b fs@c; -i @c fs@d. The incremental source may be specified as with the -i option.

 

 

-L, --large-block

Generate a stream which may contain blocks larger than 128KB. This flag has no effect if the large_blocks pool feature is disabled, or if the recordsize property of this filesystem has never been set above 128KB. The receiving system must have the large_blocks pool feature enabled as well. See zpool-features(5) for details on ZFS feature flags and the large_blocks feature.

 

 

-P, --parsable

Print machine-parsable verbose information about the stream package generated.

 

 

-R, --replicate

Generate a replication stream package, which will replicate the specified file system, and all descendent file systems, up to the named snapshot. When received, all properties, snapshots, descendent file systems, and clones are preserved.

If the -i or -I flags are used in conjunction with the -R flag, an incremental replication stream is generated. The current values of properties, and current snapshot and file system names are set when the stream is received. If the -F flag is specified when this stream is received, snapshots and file systems that do not exist on the sending side are destroyed.

 

 

-e, --embed

Generate a more compact stream by using WRITE_EMBEDDED records for blocks which are stored more compactly on disk by the embedded_data pool feature. This flag has no effect if the embedded_data feature is disabled. The receiving system must have the embedded_data feature enabled. If the lz4_compress feature is active on the sending system, then the receiving system must have that feature enabled as well. See zpool-features(5) for details on ZFS feature flags and the embedded_data feature.

 

 

-c, --compressed

Generate a more compact stream by using compressed WRITE records for blocks which are compressed on disk and in memory (see the compression property for details). If the lz4_compress feature is active on the sending system, then the receiving system must have that feature enabled as well. If the large_blocks feature is enabled on the sending system but the -L option is not supplied in conjunction with -c, then the data will be decompressed before sending so it can be split into smaller block sizes.

 

 

-i snapshot

Generate an incremental stream from the first snapshot (the incremental source) to the second snapshot (the incremental target). The incremental source can be specified as the last component of the snapshot name (the @ character and following) and it is assumed to be from the same file system as the incremental target.

If the destination is a clone, the source may be the origin snapshot, which must be fully specified (for example, pool/fs@origin, not just @origin).

 

 

-n, --dryrun

Do a dry-run (“No-op”) send. Do not generate any actual send data. This is useful in conjunction with the -v or -P flags to determine what data will be sent. In this case, the verbose output will be written to standard output (contrast with a non-dry-run, where the stream is written to standard output and the verbose output goes to standard error).

 

 

-p, --props

Include the dataset's properties in the stream. This flag is implicit when -R is specified. The receiving system must also support this feature.

 

 

-v, --verbose

Print verbose information about the stream package generated. This information includes a per-second report of how much data has been sent.

The format of the stream is committed. You will be able to receive your streams on future versions of ZFS .

 

 

zfs send [

-Lce

] [

-i snapshot|bookmark

] filesystem|volume|snapshot

Generate a send stream, which may be of a filesystem, and may be incremental from a bookmark. If the destination is a filesystem or volume, the pool must be read-only, or the filesystem must not be mounted. When the stream generated from a filesystem or volume is received, the default snapshot name will be “--head--”.

 

 

-L, --large-block

Generate a stream which may contain blocks larger than 128KB. This flag has no effect if the large_blocks pool feature is disabled, or if the recordsize property of this filesystem has never been set above 128KB. The receiving system must have the large_blocks pool feature enabled as well. See zpool-features(5) for details on ZFS feature flags and the large_blocks feature.

 

 

-c, --compressed

Generate a more compact stream by using compressed WRITE records for blocks which are compressed on disk and in memory (see the compression property for details). If the lz4_compress feature is active on the sending system, then the receiving system must have that feature enabled as well. If the large_blocks feature is enabled on the sending system but the -L option is not supplied in conjunction with -c, then the data will be decompressed before sending so it can be split into smaller block sizes.

 

 

-e, --embed

Generate a more compact stream by using WRITE_EMBEDDED records for blocks which are stored more compactly on disk by the embedded_data pool feature. This flag has no effect if the embedded_data feature is disabled. The receiving system must have the embedded_data feature enabled. If the lz4_compress feature is active on the sending system, then the receiving system must have that feature enabled as well. See zpool-features(5) for details on ZFS feature flags and the embedded_data feature.

 

 

-i snapshot|bookmark

Generate an incremental send stream. The incremental source must be an earlier snapshot in the destination's history. It will commonly be an earlier snapshot in the destination's file system, in which case it can be specified as the last component of the name (the # or @ character and following).

If the incremental target is a clone, the incremental source can be the origin snapshot, or an earlier snapshot in the origin's filesystem, or the origin's origin, etc.

 

 

zfs send [

-Penv

] -t receive_resume_token

Creates a send stream which resumes an interrupted receive. The receive_resume_token is the value of this property on the filesystem or volume that was being received into. See the documentation for zfs receive -s for more details.

 

 

zfs receive [

-Fnsuv

] [

-o origin=snapshot

] filesystem|volume|snapshot

 

zfs receive [

-Fnsuv

] [

-d|-e

] [

-o origin=snapshot

] filesystem

Creates a snapshot whose contents are as specified in the stream provided on standard input. If a full stream is received, then a new file system is created as well. Streams are created using the zfs send subcommand, which by default creates a full stream. zfs recv can be used as an alias for zfs receive.

If an incremental stream is received, then the destination file system must already exist, and its most recent snapshot must match the incremental stream's source. For zvols, the destination device link is destroyed and recreated, which means the zvol cannot be accessed during the receive operation.

When a snapshot replication package stream that is generated by using the zfs send -R command is received, any snapshots that do not exist on the sending location are destroyed by using the zfs destroy -d command.

The name of the snapshot (and file system, if a full stream is received) that this subcommand creates depends on the argument type and the use of the -d or -e options.

If the argument is a snapshot name, the specified snapshot is created. If the argument is a file system or volume name, a snapshot with the same name as the sent snapshot is created within the specified filesystem or volume. If neither of the -d or -e options are specified, the provided target snapshot name is used exactly as provided.

The -d and -e options cause the file system name of the target snapshot to be determined by appending a portion of the sent snapshot's name to the specified target filesystem. If the -d option is specified, all but the first element of the sent snapshot's file system path (usually the pool name) is used and any required intermediate file systems within the specified one are created. If the -e option is specified, then only the last element of the sent snapshot's file system name (i.e. the name of the source file system itself) is used as the target file system name.

 

 

-F

Force a rollback of the file system to the most recent snapshot before performing the receive operation. If receiving an incremental replication stream (for example, one generated by zfs send -R [

-i|-I

]), destroy snapshots and file systems that do not exist on the sending side.

 

 

-d

Discard the first element of the sent snapshot's file system name, using the remaining elements to determine the name of the target file system for the new snapshot as described in the paragraph above.

 

 

-e

Discard all but the last element of the sent snapshot's file system name, using that element to determine the name of the target file system for the new snapshot as described in the paragraph above.

 

 

-n

Do not actually receive the stream. This can be useful in conjunction with the -v option to verify the name the receive operation would use.

 

 

-o origin=snapshot

Forces the stream to be received as a clone of the given snapshot. If the stream is a full send stream, this will create the filesystem described by the stream as a clone of the specified snapshot. Which snapshot was specified will not affect the success or failure of the receive, as long as the snapshot does exist. If the stream is an incremental send stream, all the normal verification will be performed.

 

 

-u

File system that is associated with the received stream is not mounted.

 

 

-v

Print verbose information about the stream and the time required to perform the receive operation.

 

 

-s

If the receive is interrupted, save the partially received state, rather than deleting it. Interruption may be due to premature termination of the stream (e.g. due to network failure or failure of the remote system if the stream is being read over a network connection), a checksum error in the stream, termination of the zfs receive process, or unclean shutdown of the system.

The receive can be resumed with a stream generated by zfs send -t token, where the token is the value of the receive_resume_token property of the filesystem or volume which is received into.

To use this flag, the storage pool must have the extensible_dataset feature enabled. See zpool-features(5) for details on ZFS feature flags.

 

 

zfs receive -A filesystem|volume

Abort an interrupted zfs receive -s, deleting its saved partially received state.

 

 

zfs allow filesystem|volume

Displays permissions that have been delegated on the specified filesystem or volume. See the other forms of zfs allow for more information.

 

 

zfs allow [

-dglu

] user|group[

,user|group

]... perm|@setname[

,perm|@setname

]... filesystem|volume

 

zfs allow [

-dl

] -e|everyone perm|@setname[

,perm|@setname

]... filesystem|volume

Delegates ZFS administration permission for the file systems to non-privileged users.

 

 

-d

Allow only for the descendent file systems.

 

 

-e|everyone

Specifies that the permissions be delegated to everyone.

 

 

-g group[

,group

]...

Explicitly specify that permissions are delegated to the group.

 

 

-l

Allow “locally” only for the specified file system.

 

 

-u user[

,user

]...

Explicitly specify that permissions are delegated to the user.

 

 

user|group[

,user|group

]...

Specifies to whom the permissions are delegated. Multiple entities can be specified as a comma-separated list. If neither of the -gu options are specified, then the argument is interpreted preferentially as the keyword everyone, then as a user name, and lastly as a group name. To specify a user or group named “everyone”, use the -g or -u options. To specify a group with the same name as a user, use the -g options.

 

 

perm|@setname[

,perm|@setname

]...

The permissions to delegate. Multiple permissions may be specified as a comma-separated list. Permission names are the same as ZFS subcommand and property names. See the property list below. Property set names, which begin with @, may be specified. See the -s form below for details.

If neither of the -dl options are specified, or both are, then the permissions are allowed for the file system or volume, and all of its descendents.

Permissions are generally the ability to use a ZFS subcommand or change a ZFS property. The following permissions are available:

NAME             TYPE           NOTES 
allow            subcommand     Must also have the permission that is 
                                being allowed 
clone            subcommand     Must also have the 'create' ability and 
                                'mount' ability in the origin file system 
create           subcommand     Must also have the 'mount' ability 
destroy          subcommand     Must also have the 'mount' ability 
diff             subcommand     Allows lookup of paths within a dataset 
                                given an object number, and the ability 
                                to create snapshots necessary to 
                                'zfs diff'. 
mount            subcommand     Allows mount/umount of ZFS datasets 
promote          subcommand     Must also have the 'mount' and 'promote' 
                                ability in the origin file system 
receive          subcommand     Must also have the 'mount' and 'create' 
                                ability 
rename           subcommand     Must also have the 'mount' and 'create' 
                                ability in the new parent 
rollback         subcommand     Must also have the 'mount' ability 
send             subcommand 
share            subcommand     Allows sharing file systems over NFS 
                                or SMB protocols 
snapshot         subcommand     Must also have the 'mount' ability 
 
groupquota       other          Allows accessing any groupquota@... 
                                property 
groupused        other          Allows reading any groupused@... property 
userprop         other          Allows changing any user property 
userquota        other          Allows accessing any userquota@... 
                                property 
userused         other          Allows reading any userused@... property 
 
aclinherit       property 
aclmode          property 
atime            property 
canmount         property 
casesensitivity  property 
checksum         property 
compression      property 
copies           property 
devices          property 
exec             property 
filesystem_limit property 
mountpoint       property 
nbmand           property 
normalization    property 
primarycache     property 
quota            property 
readonly         property 
recordsize       property 
refquota         property 
refreservation   property 
reservation      property 
secondarycache   property 
setuid           property 
sharenfs         property 
sharesmb         property 
snapdir          property 
snapshot_limit   property 
utf8only         property 
version          property 
volblocksize     property 
volsize          property 
vscan            property 
xattr            property 
zoned            property
    

 

 

zfs allow -c perm|@setname[

,perm|@setname

]... filesystem|volume

Sets “create time” permissions. These permissions are granted (locally) to the creator of any newly-created descendent file system.

 

 

zfs allow -s @setname perm|@setname[

,perm|@setname

]... filesystem|volume

Defines or adds permissions to a permission set. The set can be used by other zfs allow commands for the specified file system and its descendents. Sets are evaluated dynamically, so changes to a set are immediately reflected. Permission sets follow the same naming restrictions as ZFS file systems, but the name must begin with @, and can be no more than 64 characters long.

 

 

zfs unallow [

-dglru

] user|group[

,user|group

]... [

perm|@setname[

,perm|@setname

]...

] filesystem|volume

 

zfs unallow [

-dlr

] -e|everyone [

perm|@setname[

,perm|@setname

]...

] filesystem|volume

 

zfs unallow [

-r

] -c [

perm|@setname[

,perm|@setname

]...

] filesystem|volume

Removes permissions that were granted with the zfs allow command. No permissions are explicitly denied, so other permissions granted are still in effect. For example, if the permission is granted by an ancestor. If no permissions are specified, then all permissions for the specified user, group, or everyone are removed. Specifying everyone (or using the -e option) only removes the permissions that were granted to everyone, not all permissions for every user and group. See the zfs allow command for a description of the -ldugec options.

 

 

-r

Recursively remove the permissions from this file system and all descendents.

 

 

zfs unallow [

-r

] -s @setname [

perm|@setname[

,perm|@setname

]...

] filesystem|volume

Removes permissions from a permission set. If no permissions are specified, then all permissions are removed, thus removing the set entirely.

 

 

zfs hold [

-r

] tag snapshot...

Adds a single reference, named with the tag argument, to the specified snapshot or snapshots. Each snapshot has its own tag namespace, and tags must be unique within that space.

If a hold exists on a snapshot, attempts to destroy that snapshot by using the zfs destroy command return EBUSY.

 

 

-r

Specifies that a hold with the given tag is applied recursively to the snapshots of all descendent file systems.

 

 

zfs holds [

-r

] snapshot...

Lists all existing user references for the given snapshot or snapshots.

 

 

-r

Lists the holds that are set on the named descendent snapshots, in addition to listing the holds on the named snapshot.

 

 

zfs release [

-r

] tag snapshot...

Removes a single reference, named with the tag argument, from the specified snapshot or snapshots. The tag must already exist for each snapshot. If a hold exists on a snapshot, attempts to destroy that snapshot by using the zfs destroy command return EBUSY.

 

 

-r

Recursively releases a hold with the given tag on the snapshots of all descendent file systems.

 

 

zfs diff [

-FHt

] snapshot snapshot|filesystem

Display the difference between a snapshot of a given filesystem and another snapshot of that filesystem from a later time or the current contents of the filesystem. The first column is a character indicating the type of change, the other columns indicate pathname, new pathname (in case of rename), change in link count, and optionally file type and/or change time. The types of change are:

-       The path has been removed 
+       The path has been created 
M       The path has been modified 
R       The path has been renamed
    

 

 

-F

Display an indication of the type of file, in a manner similar to the - option of ls(1).

B       Block device 
C       Character device 
/       Directory 
>       Door 
|       Named pipe 
@       Symbolic link 
P       Event port 
=       Socket 
F       Regular file
        

 

 

-H

Give more parsable tab-separated output, without header lines and without arrows.

 

 

-t

Display the path's inode change time as the first column of output.

 

 

zfs program [

-jn

] [

-t timeout

] [

-m memory_limit

] pool script [

arg1 ...

]

Executes script as a ZFS channel program on pool. The ZFS channel program interface allows ZFS administrative operations to be run programmatically via a Lua script. The entire script is executed atomically, with no other administrative operations taking effect concurrently. A library of ZFS calls is made available to channel program scripts. Channel programs may only be run with root privileges.

For full documentation of the ZFS channel program interface, see the manual page for zfs-program(1M).

 

 

-j

Display channel program output in JSON format. When this flag is specified and standard output is empty - channel program encountered an error. The details of such an error will be printed to standard error in plain text.

 

 

-n

Executes a read-only channel program, which runs faster. The program cannot change on-disk state by calling functions from the zfs.sync submodule. The program can be used to gather information such as properties and determining if changes would succeed (zfs.check.*). Without this flag, all pending changes must be synced to disk before a channel program can complete.

 

 

-t timeout

Execution time limit, in milliseconds. If a channel program executes for longer than the provided timeout, it will be stopped and an error will be returned. The default timeout is 1000 ms, and can be set to a maximum of 10000 ms.

 

 

-m memory-limit

Memory limit, in bytes. If a channel program attempts to allocate more memory than the given limit, it will be stopped and an error returned. The default memory limit is 10 MB, and can be set to a maximum of 100 MB.

All remaining argument strings are passed directly to the channel program as arguments. See zfs-program(1M) for more information.

EXIT STATUS

EXAMPLES

 

 

Example 1 Creating a ZFS File System Hierarchy

The following commands create a file system named pool/home and a file system named pool/home/bob. The mount point /export/home is set for the parent file system, and is automatically inherited by the child file system.

# zfs create pool/home 
# zfs set mountpoint=/export/home pool/home 
# zfs create pool/home/bob
    

 

 

Example 2 Creating a ZFS Snapshot

The following command creates a snapshot named yesterday. This snapshot is mounted on demand in the .zfs/snapshot directory at the root of the pool/home/bob file system.

# zfs snapshot pool/home/bob@yesterday
    

 

 

Example 3 Creating and Destroying Multiple Snapshots

The following command creates snapshots named yesterday of pool/home and all of its descendent file systems. Each snapshot is mounted on demand in the .zfs/snapshot directory at the root of its file system. The second command destroys the newly created snapshots.

# zfs snapshot -r pool/home@yesterday 
# zfs destroy -r pool/home@yesterday
    

 

 

Example 4 Disabling and Enabling File System Compression

The following command disables the compression property for all file systems under pool/home. The next command explicitly enables compression for pool/home/anne.

# zfs set compression=off pool/home 
# zfs set compression=on pool/home/anne
    

 

 

Example 5 Listing ZFS Datasets

The following command lists all active file systems and volumes in the system. Snapshots are displayed if the listsnaps property is on. The default is off. See zpool(1M) for more information on pool properties.

# zfs list 
NAME                      USED  AVAIL  REFER  MOUNTPOINT 
pool                      450K   457G    18K  /pool 
pool/home                 315K   457G    21K  /export/home 
pool/home/anne             18K   457G    18K  /export/home/anne 
pool/home/bob             276K   457G   276K  /export/home/bob
    

 

 

Example 6 Setting a Quota on a ZFS File System

The following command sets a quota of 50 Gbytes for pool/home/bob.

# zfs set quota=50G pool/home/bob
    

 

 

Example 7 Listing ZFS Properties

The following command lists all properties for pool/home/bob.

# zfs get all pool/home/bob 
NAME           PROPERTY              VALUE                  SOURCE 
pool/home/bob  type                  filesystem             - 
pool/home/bob  creation              Tue Jul 21 15:53 2009  - 
pool/home/bob  used                  21K                    - 
pool/home/bob  available             20.0G                  - 
pool/home/bob  referenced            21K                    - 
pool/home/bob  compressratio         1.00x                  - 
pool/home/bob  mounted               yes                    - 
pool/home/bob  quota                 20G                    local 
pool/home/bob  reservation           none                   default 
pool/home/bob  recordsize            128K                   default 
pool/home/bob  mountpoint            /pool/home/bob         default 
pool/home/bob  sharenfs              off                    default 
pool/home/bob  checksum              on                     default 
pool/home/bob  compression           on                     local 
pool/home/bob  atime                 on                     default 
pool/home/bob  devices               on                     default 
pool/home/bob  exec                  on                     default 
pool/home/bob  setuid                on                     default 
pool/home/bob  readonly              off                    default 
pool/home/bob  zoned                 off                    default 
pool/home/bob  snapdir               hidden                 default 
pool/home/bob  aclmode               discard                default 
pool/home/bob  aclinherit            restricted             default 
pool/home/bob  canmount              on                     default 
pool/home/bob  xattr                 on                     default 
pool/home/bob  copies                1                      default 
pool/home/bob  version               4                      - 
pool/home/bob  utf8only              off                    - 
pool/home/bob  normalization         none                   - 
pool/home/bob  casesensitivity       sensitive              - 
pool/home/bob  vscan                 off                    default 
pool/home/bob  nbmand                off                    default 
pool/home/bob  sharesmb              off                    default 
pool/home/bob  refquota              none                   default 
pool/home/bob  refreservation        none                   default 
pool/home/bob  primarycache          all                    default 
pool/home/bob  secondarycache        all                    default 
pool/home/bob  usedbysnapshots       0                      - 
pool/home/bob  usedbydataset         21K                    - 
pool/home/bob  usedbychildren        0                      - 
pool/home/bob  usedbyrefreservation  0                      -
    

The following command gets a single property value.

# zfs get -H -o value compression pool/home/bob 
on
    

The following command lists all properties with local settings for pool/home/bob.

# zfs get -r -s local -o name,property,value all pool/home/bob 
NAME           PROPERTY              VALUE 
pool/home/bob  quota                 20G 
pool/home/bob  compression           on
    

 

 

Example 8 Rolling Back a ZFS File System

The following command reverts the contents of pool/home/anne to the snapshot named yesterday, deleting all intermediate snapshots.

# zfs rollback -r pool/home/anne@yesterday
    

 

 

Example 9 Creating a ZFS Clone

The following command creates a writable file system whose initial contents are the same as pool/home/bob@yesterday.

# zfs clone pool/home/bob@yesterday pool/clone
    

 

 

Example 10 Promoting a ZFS Clone

The following commands illustrate how to test out changes to a file system, and then replace the original file system with the changed one, using clones, clone promotion, and renaming:

# zfs create pool/project/production 
  populate /pool/project/production with data 
# zfs snapshot pool/project/production@today 
# zfs clone pool/project/production@today pool/project/beta 
  make changes to /pool/project/beta and test them 
# zfs promote pool/project/beta 
# zfs rename pool/project/production pool/project/legacy 
# zfs rename pool/project/beta pool/project/production 
  once the legacy version is no longer needed, it can be destroyed 
# zfs destroy pool/project/legacy
    

 

 

Example 11 Inheriting ZFS Properties

The following command causes pool/home/bob and pool/home/anne to inherit the checksum property from their parent.

# zfs inherit checksum pool/home/bob pool/home/anne
    

 

 

Example 12 Remotely Replicating ZFS Data

The following commands send a full stream and then an incremental stream to a remote machine, restoring them into poolB/received/fs@a and poolB/received/fs@b, respectively. poolB must contain the file system poolB/received, and must not initially contain poolB/received/fs.

# zfs send pool/fs@a | \ 
  ssh host zfs receive poolB/received/fs@a 
# zfs send -i a pool/fs@b | \ 
  ssh host zfs receive poolB/received/fs
    

 

 

Example 13 Using the zfs receive -d Option

The following command sends a full stream of poolA/fsA/fsB@snap to a remote machine, receiving it into poolB/received/fsA/fsB@snap. The fsA/fsB@snap portion of the received snapshot's name is determined from the name of the sent snapshot. poolB must contain the file system poolB/received. If poolB/received/fsA does not exist, it is created as an empty file system.

# zfs send poolA/fsA/fsB@snap | \ 
  ssh host zfs receive -d poolB/received
    

 

 

Example 14 Setting User Properties

The following example sets the user-defined com.example:department property for a dataset.

# zfs set com.example:department=12345 tank/accounting
    

 

 

Example 15 Performing a Rolling Snapshot

The following example shows how to maintain a history of snapshots with a consistent naming scheme. To keep a week's worth of snapshots, the user destroys the oldest snapshot, renames the remaining snapshots, and then creates a new snapshot, as follows:

# zfs destroy -r pool/users@7daysago 
# zfs rename -r pool/users@6daysago @7daysago 
# zfs rename -r pool/users@5daysago @6daysago 
# zfs rename -r pool/users@4daysago @5daysago 
# zfs rename -r pool/users@3daysago @4daysago 
# zfs rename -r pool/users@2daysago @3daysago 
# zfs rename -r pool/users@yesterday @2daysago 
# zfs rename -r pool/users@today @yesterday 
# zfs snapshot -r pool/users@today
    

 

 

Example 16 Setting sharenfs Property Options on a ZFS File System

The following commands show how to set sharenfs property options to enable rw access for a set of IP addresses and to enable root access for system neo on the tank/home file system.

# zfs set sharenfs='rw=@123.123.0.0/16,root=neo' tank/home
    

If you are using DNS for host name resolution, specify the fully qualified hostname.

 

 

Example 17 Delegating ZFS Administration Permissions on a ZFS Dataset

The following example shows how to set permissions so that user cindys can create, destroy, mount, and take snapshots on tank/cindys. The permissions on tank/cindys are also displayed.

# zfs allow cindys create,destroy,mount,snapshot tank/cindys 
# zfs allow tank/cindys 
---- Permissions on tank/cindys -------------------------------------- 
Local+Descendent permissions: 
        user cindys create,destroy,mount,snapshot
    

Because the tank/cindys mount point permission is set to 755 by default, user cindys will be unable to mount file systems under tank/cindys. Add an ACE similar to the following syntax to provide mount point access:

# chmod A+user:cindys:add_subdirectory:allow /tank/cindys
    

 

 

Example 18 Delegating Create Time Permissions on a ZFS Dataset

The following example shows how to grant anyone in the group staff to create file systems in tank/users. This syntax also allows staff members to destroy their own file systems, but not destroy anyone else's file system. The permissions on tank/users are also displayed.

# zfs allow staff create,mount tank/users 
# zfs allow -c destroy tank/users 
# zfs allow tank/users 
---- Permissions on tank/users --------------------------------------- 
Permission sets: 
        destroy 
Local+Descendent permissions: 
        group staff create,mount
    

 

 

Example 19 Defining and Granting a Permission Set on a ZFS Dataset

The following example shows how to define and grant a permission set on the tank/users file system. The permissions on tank/users are also displayed.

# zfs allow -s @pset create,destroy,snapshot,mount tank/users 
# zfs allow staff @pset tank/users 
# zfs allow tank/users 
---- Permissions on tank/users --------------------------------------- 
Permission sets: 
        @pset create,destroy,mount,snapshot 
Local+Descendent permissions: 
        group staff @pset
    

 

 

Example 20 Delegating Property Permissions on a ZFS Dataset

The following example shows to grant the ability to set quotas and reservations on the users/home file system. The permissions on users/home are also displayed.

# zfs allow cindys quota,reservation users/home 
# zfs allow users/home 
---- Permissions on users/home --------------------------------------- 
Local+Descendent permissions: 
        user cindys quota,reservation 
cindys% zfs set quota=10G users/home/marks 
cindys% zfs get quota users/home/marks 
NAME              PROPERTY  VALUE  SOURCE 
users/home/marks  quota     10G    local
    

 

 

Example 21 Removing ZFS Delegated Permissions on a ZFS Dataset

The following example shows how to remove the snapshot permission from the staff group on the tank/users file system. The permissions on tank/users are also displayed.

# zfs unallow staff snapshot tank/users 
# zfs allow tank/users 
---- Permissions on tank/users --------------------------------------- 
Permission sets: 
        @pset create,destroy,mount,snapshot 
Local+Descendent permissions: 
        group staff @pset
    

 

 

Example 22 Showing the differences between a snapshot and a ZFS Dataset

The following example shows how to see what has changed between a prior snapshot of a ZFS dataset and its current state. The -F option is used to indicate type information for the files affected.

# zfs diff -F tank/test@before tank/test 
M       /       /tank/test/ 
M       F       /tank/test/linked      (+1) 
R       F       /tank/test/oldname -> /tank/test/newname 
-       F       /tank/test/deleted 
+       F       /tank/test/created 
M       F       /tank/test/modified
    

INTERFACE STABILITY

SEE ALSO