1 '\" te
2 .\" Copyright (c) 2012 by Delphix. All rights reserved.
3 .\" The contents of this file are subject to the terms of the Common Development
4 .\" and Distribution License (the "License"). You may not use this file except
5 .\" in compliance with the License. You can obtain a copy of the license at
6 .\" usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.
7 .\"
8 .\" See the License for the specific language governing permissions and
9 .\" limitations under the License. When distributing Covered Code, include this
10 .\" CDDL HEADER in each file and include the License file at
11 .\" usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this
12 .\" CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your
13 .\" own identifying information:
14 .\" Portions Copyright [yyyy] [name of copyright owner]
15 .TH ZPOOL-FEATURES 5 "Mar 16, 2012"
16 .SH NAME
17 zpool\-features \- ZFS pool feature descriptions
18 .SH DESCRIPTION
19 .sp
20 .LP
21 ZFS pool on\-disk format versions are specified via "features" which replace
22 the old on\-disk format numbers (the last supported on\-disk format number is
23 28). To enable a feature on a pool use the \fBupgrade\fR subcommand of the
24 \fBzpool\fR(1M) command, or set the \fBfeature@\fR\fIfeature_name\fR property
25 to \fBenabled\fR.
26 .sp
27 .LP
28 The pool format does not affect file system version compatibility or the ability
29 to send file systems between pools.
30 .sp
31 .LP
32 Since most features can be enabled independently of each other the on\-disk
33 format of the pool is specified by the set of all features marked as
34 \fBactive\fR on the pool. If the pool was created by another software version
35 this set may include unsupported features.
153 DEPENDENCIES none
154 .TE
155
156 Destroying a file system requires traversing all of its data in order to
157 return its used space to the pool. Without \fBasync_destroy\fR the file system
158 is not fully removed until all space has been reclaimed. If the destroy
159 operation is interrupted by a reboot or power outage the next attempt to open
160 the pool will need to complete the destroy operation synchronously.
161
162 When \fBasync_destroy\fR is enabled the file system's data will be reclaimed
163 by a background process, allowing the destroy operation to complete without
164 traversing the entire file system. The background process is able to resume
165 interrupted destroys after the pool has been opened, eliminating the need
166 to finish interrupted destroys as part of the open operation. The amount
167 of space remaining to be reclaimed by the background process is available
168 through the \fBfreeing\fR property.
169
170 This feature is only \fBactive\fR while \fBfreeing\fR is non\-zero.
171 .RE
172
173 .sp
174 .ne 2
175 .na
176 \fB\fBempty_bpobj\fR\fR
177 .ad
178 .RS 4n
179 .TS
180 l l .
181 GUID com.delphix:empty_bpobj
182 READ\-ONLY COMPATIBLE yes
183 DEPENDENCIES none
184 .TE
185
186 This feature increases the performance of creating and using a large
187 number of snapshots of a single filesystem or volume, and also reduces
188 the disk space required.
189
190 When there are many snapshots, each snapshot uses many Block Pointer
191 Objects (bpobj's) to track blocks associated with that snapshot.
192 However, in common use cases, most of these bpobj's are empty. This
|
1 '\" te
2 .\" Copyright (c) 2012 by Delphix. All rights reserved.
3 .\" Copyright (c) 2012 Joyent, Inc. All rights reserved.
4 .\" The contents of this file are subject to the terms of the Common Development
5 .\" and Distribution License (the "License"). You may not use this file except
6 .\" in compliance with the License. You can obtain a copy of the license at
7 .\" usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.
8 .\"
9 .\" See the License for the specific language governing permissions and
10 .\" limitations under the License. When distributing Covered Code, include this
11 .\" CDDL HEADER in each file and include the License file at
12 .\" usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this
13 .\" CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your
14 .\" own identifying information:
15 .\" Portions Copyright [yyyy] [name of copyright owner]
16 .TH ZPOOL-FEATURES 5 "Oct 24, 2012"
17 .SH NAME
18 zpool\-features \- ZFS pool feature descriptions
19 .SH DESCRIPTION
20 .sp
21 .LP
22 ZFS pool on\-disk format versions are specified via "features" which replace
23 the old on\-disk format numbers (the last supported on\-disk format number is
24 28). To enable a feature on a pool use the \fBupgrade\fR subcommand of the
25 \fBzpool\fR(1M) command, or set the \fBfeature@\fR\fIfeature_name\fR property
26 to \fBenabled\fR.
27 .sp
28 .LP
29 The pool format does not affect file system version compatibility or the ability
30 to send file systems between pools.
31 .sp
32 .LP
33 Since most features can be enabled independently of each other the on\-disk
34 format of the pool is specified by the set of all features marked as
35 \fBactive\fR on the pool. If the pool was created by another software version
36 this set may include unsupported features.
154 DEPENDENCIES none
155 .TE
156
157 Destroying a file system requires traversing all of its data in order to
158 return its used space to the pool. Without \fBasync_destroy\fR the file system
159 is not fully removed until all space has been reclaimed. If the destroy
160 operation is interrupted by a reboot or power outage the next attempt to open
161 the pool will need to complete the destroy operation synchronously.
162
163 When \fBasync_destroy\fR is enabled the file system's data will be reclaimed
164 by a background process, allowing the destroy operation to complete without
165 traversing the entire file system. The background process is able to resume
166 interrupted destroys after the pool has been opened, eliminating the need
167 to finish interrupted destroys as part of the open operation. The amount
168 of space remaining to be reclaimed by the background process is available
169 through the \fBfreeing\fR property.
170
171 This feature is only \fBactive\fR while \fBfreeing\fR is non\-zero.
172 .RE
173
174 .sp
175 .ne 2
176 .na
177 \fB\fBdataset_quota\fR\fR
178 .ad
179 .RS 4n
180 .TS
181 l l .
182 GUID com.joyent:dataset_quota
183 READ\-ONLY COMPATIBLE yes
184 DEPENDENCIES none
185 .TE
186
187 This feature enables dataset quotas and snapshot quotas. These quotas
188 can be used to limit how many datasets and/or snapshots can be created
189 under the dataset on which the quotas are set.
190
191 This feature is \fBactive\fR once either of the quota properties has been
192 set on a dataset.
193 .RE
194
195 .sp
196 .ne 2
197 .na
198 \fB\fBempty_bpobj\fR\fR
199 .ad
200 .RS 4n
201 .TS
202 l l .
203 GUID com.delphix:empty_bpobj
204 READ\-ONLY COMPATIBLE yes
205 DEPENDENCIES none
206 .TE
207
208 This feature increases the performance of creating and using a large
209 number of snapshots of a single filesystem or volume, and also reduces
210 the disk space required.
211
212 When there are many snapshots, each snapshot uses many Block Pointer
213 Objects (bpobj's) to track blocks associated with that snapshot.
214 However, in common use cases, most of these bpobj's are empty. This
|