diff options
Diffstat (limited to 'man/man5/zpool-features.5')
| -rw-r--r-- | man/man5/zpool-features.5 | 1705 |
1 files changed, 735 insertions, 970 deletions
diff --git a/man/man5/zpool-features.5 b/man/man5/zpool-features.5 index c97870dbb..2b4cee545 100644 --- a/man/man5/zpool-features.5 +++ b/man/man5/zpool-features.5 @@ -1,4 +1,4 @@ -'\" te +.\" .\" Copyright (c) 2012, 2018 by Delphix. All rights reserved. .\" Copyright (c) 2013 by Saso Kiselkov. All rights reserved. .\" Copyright (c) 2014, Joyent, Inc. All rights reserved. @@ -17,183 +17,195 @@ .\" Copyright (c) 2019, Klara Inc. .\" Copyright (c) 2019, Allan Jude .\" Copyright (c) 2021, Colm Buckley <[email protected]> -.TH ZPOOL-FEATURES 5 "Aug 24, 2020" OpenZFS -.SH NAME -zpool\-features \- ZFS pool feature descriptions -.SH DESCRIPTION -.sp -.LP -ZFS pool on\-disk format versions are specified via "features" which replace -the old on\-disk format numbers (the last supported on\-disk format number is -28). To enable a feature on a pool use the \fBupgrade\fR subcommand of the -zpool(8) command, or set the \fBfeature@\fR\fIfeature_name\fR property -to \fBenabled\fR. Please also see the \fB"Compatibility feature sets"\fR +.\" +.Dd May 31, 2021 +.Dt ZPOOL-FEATURES 5 +.Os +. +.Sh NAME +.Nm zpool-features +.Nd description of ZFS pool features +. +.Sh DESCRIPTION +ZFS pool on-disk format versions are specified via "features" which replace +the old on-disk format numbers (the last supported on-disk format number is 28). +To enable a feature on a pool use the +.Nm zpool Cm upgrade , +or set the +.Sy feature Ns @ Ns Ar feature-name +property to +.Sy enabled . +Please also see the +.Sx Compatibility feature sets section for information on how sets of features may be enabled together. -.sp -.LP +.Pp The pool format does not affect file system version compatibility or the ability to send file systems between pools. -.sp -.LP -Since most features can be enabled independently of each other the on\-disk +.Pp +Since most features can be enabled independently of each other, the on-disk format of the pool is specified by the set of all features marked as -\fBactive\fR on the pool. If the pool was created by another software version +.Sy active +on the pool. +If the pool was created by another software version this set may include unsupported features. -.SS "Identifying features" -.sp -.LP -Every feature has a GUID of the form \fIcom.example:feature_name\fR. The -reversed DNS name ensures that the feature's GUID is unique across all ZFS -implementations. When unsupported features are encountered on a pool they will -be identified by their GUIDs. Refer to the documentation for the ZFS +. +.Ss Identifying features +Every feature has a GUID of the form +.Ar com.example : Ns Ar feature-name . +The reversed DNS name ensures that the feature's GUID is unique across all ZFS +implementations. +When unsupported features are encountered on a pool they will +be identified by their GUIDs. +Refer to the documentation for the ZFS implementation that created the pool for information about those features. -.sp -.LP -Each supported feature also has a short name. By convention a feature's short -name is the portion of its GUID which follows the ':' (e.g. -\fIcom.example:feature_name\fR would have the short name \fIfeature_name\fR), +.Pp +Each supported feature also has a short name. +By convention a feature's short name is the portion of its GUID which follows the +.Sq \&: +(i.e. +.Ar com.example : Ns Ar feature-name +would have the short name +.Ar feature-name ) , however a feature's short name may differ across ZFS implementations if following the convention would result in name conflicts. -.SS "Feature states" -.sp -.LP +. +.Ss Feature states Features can be in one of three states: -.sp -.ne 2 -.na -\fBactive\fR -.ad -.RS 12n -This feature's on\-disk format changes are in effect on the pool. Support for -this feature is required to import the pool in read\-write mode. If this -feature is not read-only compatible, support is also required to import the pool -in read\-only mode (see "Read\-only compatibility"). -.RE - -.sp -.ne 2 -.na -\fBenabled\fR -.ad -.RS 12n +.Bl -tag -width "disabled" +.It Sy active +This feature's on-disk format changes are in effect on the pool. +Support for this feature is required to import the pool in read-write mode. +If this feature is not read-only compatible, +support is also required to import the pool in read-only mode +.Pq see Sx Read-only compatibility . +.It Sy enabled An administrator has marked this feature as enabled on the pool, but the -feature's on\-disk format changes have not been made yet. The pool can still be -imported by software that does not support this feature, but changes may be made -to the on\-disk format at any time which will move the feature to the -\fBactive\fR state. Some features may support returning to the \fBenabled\fR -state after becoming \fBactive\fR. See feature\-specific documentation for -details. -.RE - -.sp -.ne 2 -.na -\fBdisabled\fR -.ad -.RS 12n -This feature's on\-disk format changes have not been made and will not be made -unless an administrator moves the feature to the \fBenabled\fR state. Features -cannot be disabled once they have been enabled. -.RE - -.sp -.LP +feature's on-disk format changes have not been made yet. +The pool can still be imported by software that does not support this feature, +but changes may be made to the on-disk format at any time +which will move the feature to the +.Sy active +state. +Some features may support returning to the +.Sy enabled +state after becoming +.Sy active . +See feature-specific documentation for details. +.It Sy disabled +This feature's on-disk format changes have not been made and will not be made +unless an administrator moves the feature to the +.Sy enabled +state. +Features cannot be disabled once they have been enabled. +.El +.Pp The state of supported features is exposed through pool properties of the form -\fIfeature@short_name\fR. -.SS "Read\-only compatibility" -.sp -.LP -Some features may make on\-disk format changes that do not interfere with other -software's ability to read from the pool. These features are referred to as -"read\-only compatible". If all unsupported features on a pool are read\-only -compatible, the pool can be imported in read\-only mode by setting the -\fBreadonly\fR property during import (see zpool(8) for details on -importing pools). -.SS "Unsupported features" -.sp -.LP -For each unsupported feature enabled on an imported pool a pool property -named \fIunsupported@feature_name\fR will indicate why the import was allowed -despite the unsupported feature. Possible values for this property are: - -.sp -.ne 2 -.na -\fBinactive\fR -.ad -.RS 12n -The feature is in the \fBenabled\fR state and therefore the pool's on\-disk +.Sy feature Ns @ Ns Ar short-name . +. +.Ss Read-only compatibility +Some features may make on-disk format changes that do not interfere with other +software's ability to read from the pool. +These features are referred to as +.Dq read-only compatible . +If all unsupported features on a pool are read-only compatible, +the pool can be imported in read-only mode by setting the +.Sy readonly +property during import (see +.Xr zpool-import 8 +for details on importing pools). +. +.Ss Unsupported features +For each unsupported feature enabled on an imported pool, a pool property +named +.Sy unsupported Ns @ Ns Ar feature-name +will indicate why the import was allowed despite the unsupported feature. +Possible values for this property are: +.Bl -tag -width "readonly" +.It Sy inactive +The feature is in the +.Sy enabled +state and therefore the pool's on-disk format is still compatible with software that does not support this feature. -.RE - -.sp -.ne 2 -.na -\fBreadonly\fR -.ad -.RS 12n -The feature is read\-only compatible and the pool has been imported in -read\-only mode. -.RE - -.SS "Feature dependencies" -.sp -.LP -Some features depend on other features being enabled in order to function -properly. Enabling a feature will automatically enable any features it -depends on. - -.SS "Compatibility feature sets" -.sp -.LP +.It Sy readonly +The feature is read-only compatible and the pool has been imported in +read-only mode. +.El +. +.Ss Feature dependencies +Some features depend on other features being enabled in order to function. +Enabling a feature will automatically enable any features it depends on. +. +.Ss Compatibility feature sets It is sometimes necessary for a pool to maintain compatibility with a -specific on\-disk format, by enabling and disabling particular features. The -\fBcompatibility\fR feature facilitates this by allowing feature sets to -be read from text files. When set to \fBoff\fR (the default); compatibility -feature sets are disabled (ie: all features are enabled); when set to -\fBlegacy\fR; no features are enabled. When set to a comma\-separated list -of filenames (each filename may either be an absolute path, or relative to -\fB/etc/zfs/compatibility.d\fR or \fB/usr/share/zfs/compatibility.d\fR) -the lists of requested features are read from those files, separated by -whitespace and/or commas. Only features present in all files are enabled. -.LP -Simple sanity checks are applied to the files; they must be between 1 and -16,384 bytes in size, and must end with a newline character. -.LP +specific on-disk format, by enabling and disabling particular features. +The +.Sy compatibility +feature facilitates this by allowing feature sets to be read from text files. +When set to +.Sy off +(the default), compatibility feature sets are disabled +(i.e. all features are enabled); when set to +.Sy legacy , +no features are enabled. +When set to a comma-separated list of filenames +(each filename may either be an absolute path, or relative to +.Pa /etc/zfs/compatibility.d +or +.Pa /usr/share/zfs/compatibility.d ) , +the lists of requested features are read from those files, +separated by whitespace and/or commas. +Only features present in all files are enabled. +.Pp +Simple sanity checks are applied to the files: +they must be between 1B and 16kB in size, and must end with a newline character. +.Pp The requested features are applied when a pool is created using -\fBzpool create \-o compatibility=...\fR and controls which features are -enabled when using \fBzpool upgrade\fR. \fBzpool status\fR +.Nm zpool Cm create Fl o Sy compatibility Ns = Ns Ar … +and controls which features are enabled when using +.Nm zpool Cm upgrade . +.Nm zpool Cm status will not show a warning about disabled features which are not part of the requested feature set. -.LP -The special value \fBlegacy\fR prevents any features from being enabled, -either via \fBzpool upgrade\fR or via \fBzpool set feature@XX=enabled\fR. -This setting also prevents pools from being upgraded to newer on-disk -versions. This is a safety measure to prevent new features from being +.Pp +The special value +.Sy legacy +prevents any features from being enabled, either via +.Nm zpool Cm upgrade +or +.Nm zpool Cm set Sy feature Ns @ Ns Ar feature-name Ns = Ns Sy enabled . +This setting also prevents pools from being upgraded to newer on-disk versions. +This is a safety measure to prevent new features from being accidentally enabled, breaking compatibility. -.LP -By convention, compatibility files in \fB/usr/share/zfs/compatibility.d\fR -are provided by the distribution package, and include feature sets +.Pp +By convention, compatibility files in +.Pa /usr/share/zfs/compatibility.d +are provided by the distribution, and include feature sets supported by important versions of popular distributions, and feature -sets commonly supported at the start of each year. Compatibility files -in \fB/etc/zfs/compatibility.d\fR, if present, will take precedence over -files with the same name in \fB/usr/share/zfs/compatibility.d\fR. -.LP +sets commonly supported at the start of each year. +Compatibility files in +.Pa /etc/zfs/compatibility.d , +if present, will take precedence over files with the same name in +.Pa /usr/share/zfs/compatibility.d . +.Pp If an unrecognized feature is found in these files, an error message will -be shown. If the unrecognized feature is in a file in -\fB/etc/zfs/compatibility.d\fR, this is treated as an error and processing -will stop. If the unrecognized feature is under -\fB/usr/share/zfs/compatibility.d\fR, this is treated as a warning and -processing will continue. This difference is to allow distributions to -include features which might not be recognized by the currently-installed -binaries. -.LP -Compatibility files may include comments; any text from \fB#\fR to the end -of the line is ignored. -.LP -\fBExample:\fR -.EX -# \fBcat /usr/share/zfs/compatibility.d/grub2\fR +be shown. +If the unrecognized feature is in a file in +.Pa /etc/zfs/compatibility.d , +this is treated as an error and processing will stop. +If the unrecognized feature is under +.Pa /usr/share/zfs/compatibility.d , +this is treated as a warning and processing will continue. +This difference is to allow distributions to include features +which might not be recognized by the currently-installed binaries. +.Pp +Compatibility files may include comments: +any text from +.Sq # +to the end of the line is ignored. +.Pp +.Sy Example : +.Bd -literal -compact -offset 4n +.No example# Nm cat Pa /usr/share/zfs/compatibility.d/grub2 # Features which are supported by GRUB2 async_destroy bookmarks @@ -207,871 +219,624 @@ large_blocks lz4_compress spacemap_histogram -# \fBzpool create \-o compatibility=grub2 bootpool vdev\fR -.EE -.LP -See \fBzpool\-create(8)\fR and \fBzpool\-upgrade(8)\fR for more information -on how these commands are affected by feature sets. -.SH FEATURES -.sp -.LP +.No example# Nm zpool Cm create Fl o Sy compatibility Ns = Ns Ar grub2 Ar bootpool Ar vdev +.Ed +.Pp +See +.Xr zpool-create 8 +and +.Xr zpool-upgrade 8 +for more information on how these commands are affected by feature sets. +. +.de feature +.It Sy \\$2 +.Bl -tag -compact -width "READ-ONLY COMPATIBLE" +.It GUID +.Sy \\$1:\\$2 +.if !"\\$4"" \{\ +.It DEPENDENCIES +\fB\\$4\fP\c +.if !"\\$5"" , \fB\\$5\fP\c +.if !"\\$6"" , \fB\\$6\fP\c +.if !"\\$7"" , \fB\\$7\fP\c +.if !"\\$8"" , \fB\\$8\fP\c +.if !"\\$9"" , \fB\\$9\fP\c +.\} +.It READ-ONLY COMPATIBLE +\\$3 +.El +.Pp +.. +. +.ds instant-never \ +.No This feature becomes Sy active No as soon as it is enabled \ +and will never return to being Sy enabled . +. +.ds remount-upgrade \ +.No Each filesystem will be upgraded automatically when remounted, \ +or when a new file is created under that filesystem. \ +The upgrade can also be triggered on filesystems via \ +Nm zfs Cm set Sy version Ns = Ns Sy current Ar fs . \ +No The upgrade process runs in the background and may take a while to complete \ +for filesystems containing large amounts of files. +. +.de checksum-spiel +When the +.Sy \\$1 +feature is set to +.Sy enabled , +the administrator can turn on the +.Sy \\$1 +checksum on any dataset using +.Nm zfs Cm set Sy checksum Ns = Ns Sy \\$1 Ar dset +.Po see Xr zfs-set 8 Pc . +This feature becomes +.Sy active +once a +.Sy checksum +property has been set to +.Sy \\$1 , +and will return to being +.Sy enabled +once all filesystems that have ever had their checksum set to +.Sy \\$1 +are destroyed. +.. +. +.Sh FEATURES The following features are supported on this system: - -.sp -.ne 2 -.na -\fBallocation_classes\fR -.ad -.RS 4n -.TS -l l . -GUID org.zfsonlinux:allocation_classes -READ\-ONLY COMPATIBLE yes -DEPENDENCIES none -.TE - +.Bl -tag -width Ds +.feature org.zfsonlinux allocation_classes yes This feature enables support for separate allocation classes. - -This feature becomes \fBactive\fR when a dedicated allocation class vdev -(dedup or special) is created with the \fBzpool create\fR or \fBzpool add\fR -subcommands. With device removal, it can be returned to the \fBenabled\fR +.Pp +This feature becomes +.Sy active +when a dedicated allocation class vdev (dedup or special) is created with the +.Nm zpool Cm create No or Nm zpool Cm add No commands . +With device removal, it can be returned to the +.Sy enabled state if all the dedicated allocation class vdevs are removed. -.RE - -.sp -.ne 2 -.na -\fBasync_destroy\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:async_destroy -READ\-ONLY COMPATIBLE yes -DEPENDENCIES none -.TE - +. +.feature com.delphix async_destroy yes Destroying a file system requires traversing all of its data in order to -return its used space to the pool. Without \fBasync_destroy\fR the file system -is not fully removed until all space has been reclaimed. If the destroy -operation is interrupted by a reboot or power outage the next attempt to open -the pool will need to complete the destroy operation synchronously. - -When \fBasync_destroy\fR is enabled the file system's data will be reclaimed -by a background process, allowing the destroy operation to complete without -traversing the entire file system. The background process is able to resume +return its used space to the pool. +Without +.Sy async_destroy , +the file system is not fully removed until all space has been reclaimed. +If the destroy operation is interrupted by a reboot or power outage, +the next attempt to open the pool will need to complete the destroy +operation synchronously. +.Pp +When +.Sy async_destroy +is enabled, the file system's data will be reclaimed by a background process, +allowing the destroy operation to complete +without traversing the entire file system. +The background process is able to resume interrupted destroys after the pool has been opened, eliminating the need -to finish interrupted destroys as part of the open operation. The amount -of space remaining to be reclaimed by the background process is available -through the \fBfreeing\fR property. - -This feature is only \fBactive\fR while \fBfreeing\fR is non\-zero. -.RE - -.sp -.ne 2 -.na -\fBbookmarks\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:bookmarks -READ\-ONLY COMPATIBLE yes -DEPENDENCIES extensible_dataset -.TE - -This feature enables use of the \fBzfs bookmark\fR subcommand. - -This feature is \fBactive\fR while any bookmarks exist in the pool. +to finish interrupted destroys as part of the open operation. +The amount of space remaining to be reclaimed by the background process +is available through the +.Sy freeing +property. +.Pp +This feature is only +.Sy active +while +.Sy freeing +is non-zero. +. +.feature com.delphix bookmarks yes extensible_dataset +This feature enables use of the +.Nm zfs Cm bookmark +command. +.Pp +This feature is +.Sy active +while any bookmarks exist in the pool. All bookmarks in the pool can be listed by running -\fBzfs list -t bookmark -r \fIpoolname\fR\fR. -.RE - -.sp -.ne 2 -.na -\fBbookmark_v2\fR -.ad -.RS 4n -.TS -l l . -GUID com.datto:bookmark_v2 -READ\-ONLY COMPATIBLE no -DEPENDENCIES bookmark, extensible_dataset -.TE - +.Nm zfs Cm list Fl t Sy bookmark Fl r Ar poolname . +. +.feature com.datto bookmark_v2 no bookmark extensible_dataset This feature enables the creation and management of larger bookmarks which are needed for other features in ZFS. - -This feature becomes \fBactive\fR when a v2 bookmark is created and will be -returned to the \fBenabled\fR state when all v2 bookmarks are destroyed. -.RE - -.sp -.ne 2 -.na -\fBbookmark_written\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:bookmark_written -READ\-ONLY COMPATIBLE no -DEPENDENCIES bookmark, extensible_dataset, bookmark_v2 -.TE - +.Pp +This feature becomes +.Sy active +when a v2 bookmark is created and will be returned to the +.Sy enabled +state when all v2 bookmarks are destroyed. +. +.feature com.delphix bookmark_written no bookmark extensible_dataset bookmark_v2 This feature enables additional bookmark accounting fields, enabling the -written#<bookmark> property (space written since a bookmark) and estimates of +.Sy written Ns # Ns Ar bookmark +property (space written since a bookmark) and estimates of send stream sizes for incrementals from bookmarks. - -This feature becomes \fBactive\fR when a bookmark is created and will be -returned to the \fBenabled\fR state when all bookmarks with these fields are destroyed. -.RE - -.sp -.ne 2 -.na -\fBdevice_rebuild\fR -.ad -.RS 4n -.TS -l l . -GUID org.openzfs:device_rebuild -READ\-ONLY COMPATIBLE yes -DEPENDENCIES none -.TE - -This feature enables the ability for the \fBzpool attach\fR and \fBzpool -replace\fR subcommands to perform sequential reconstruction (instead of -healing reconstruction) when resilvering. - +.Pp +This feature becomes +.Sy active +when a bookmark is created and will be +returned to the +.Sy enabled +state when all bookmarks with these fields are destroyed. +. +.feature org.openzfs device_rebuild yes +This feature enables the ability for the +.Nm zpool Cm attach +and +.Nm zpool Cm replace +commands to perform sequential reconstruction +(instead of healing reconstruction) when resilvering. +.Pp Sequential reconstruction resilvers a device in LBA order without immediately -verifying the checksums. Once complete a scrub is started which then verifies -the checksums. This approach allows full redundancy to be restored to the pool -in the minimum amount of time. This two phase approach will take longer than a -healing resilver when the time to verify the checksums is included. However, -unless there is additional pool damage no checksum errors should be reported -by the scrub. This feature is incompatible with raidz configurations. - -This feature becomes \fBactive\fR while a sequential resilver is in progress, -and returns to \fBenabled\fR when the resilver completes. -.RE - -.sp -.ne 2 -.na -\fBdevice_removal\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:device_removal -READ\-ONLY COMPATIBLE no -DEPENDENCIES none -.TE - -This feature enables the \fBzpool remove\fR subcommand to remove top-level -vdevs, evacuating them to reduce the total size of the pool. - -This feature becomes \fBactive\fR when the \fBzpool remove\fR subcommand is used -on a top-level vdev, and will never return to being \fBenabled\fR. -.RE - -.sp -.ne 2 -.na -\fBdraid\fR -.ad -.RS 4n -.TS -l l . -GUID org.openzfs:draid -READ\-ONLY COMPATIBLE no -DEPENDENCIES none -.TE - -This feature enables use of the \fBdraid\fR vdev type. dRAID is a variant -of raidz which provides integrated distributed hot spares that allow faster -resilvering while retaining the benefits of raidz. Data, parity, and spare -space are organized in redundancy groups and distributed evenly over all of -the devices. - -This feature becomes \fBactive\fR when creating a pool which uses the -\fBdraid\fR vdev type, or when adding a new \fBdraid\fR vdev to an -existing pool. -.RE - -.sp -.ne 2 -.na -\fBedonr\fR -.ad -.RS 4n -.TS -l l . -GUID org.illumos:edonr -READ\-ONLY COMPATIBLE no -DEPENDENCIES extensible_dataset -.TE - +verifying the checksums. +Once complete, a scrub is started, which then verifies the checksums. +This approach allows full redundancy to be restored to the pool +in the minimum amount of time. +This two-phase approach will take longer than a healing resilver +when the time to verify the checksums is included. +However, unless there is additional pool damage, +no checksum errors should be reported by the scrub. +This feature is incompatible with raidz configurations. +. +This feature becomes +.Sy active +while a sequential resilver is in progress, and returns to +.Sy enabled +when the resilver completes. +. +.feature com.delphix device_removal no +This feature enables the +.Nm zpool Cm remove +command to remove top-level vdevs, +evacuating them to reduce the total size of the pool. +.Pp +This feature becomes +.Sy active +when the +.Nm zpool Cm remove +command is used +on a top-level vdev, and will never return to being +.Sy enabled . +. +.feature org.openzfs draid no +This feature enables use of the +.Sy draid +vdev type. +dRAID is a variant of raidz which provides integrated distributed +hot spares that allow faster resilvering while retaining the benefits of raidz. +Data, parity, and spare space are organized in redundancy groups +and distributed evenly over all of the devices. +.Pp +This feature becomes +.Sy active +when creating a pool which uses the +.Sy draid +vdev type, or when adding a new +.Sy draid +vdev to an existing pool. +. +.feature org.illumos edonr no extensible_dataset This feature enables the use of the Edon-R hash algorithm for checksum, including for nopwrite (if compression is also enabled, an overwrite of a block whose checksum matches the data being written will be ignored). In an abundance of caution, Edon-R requires verification when used with -dedup: \fBzfs set dedup=edonr,verify\fR. See \fBzfs\fR(8). - +dedup: +.Nm zfs Cm set Sy dedup Ns = Ns Sy edonr , Ns Sy verify +.Po see Xr zfs-set 8 Pc . +.Pp Edon-R is a very high-performance hash algorithm that was part -of the NIST SHA-3 competition. It provides extremely high hash -performance (over 350% faster than SHA-256), but was not selected -because of its unsuitability as a general purpose secure hash algorithm. +of the NIST SHA-3 competition. +It provides extremely high hash performance (over 350% faster than SHA-256), +but was not selected because of its unsuitability +as a general purpose secure hash algorithm. This implementation utilizes the new salted checksumming functionality in ZFS, which means that the checksum is pre-seeded with a secret 256-bit random key (stored on the pool) before being fed the data block -to be checksummed. Thus the produced checksums are unique to a given -pool. - -When the \fBedonr\fR feature is set to \fBenabled\fR, the administrator -can turn on the \fBedonr\fR checksum on any dataset using the -\fBzfs set checksum=edonr\fR. See zfs(8). This feature becomes -\fBactive\fR once a \fBchecksum\fR property has been set to \fBedonr\fR, -and will return to being \fBenabled\fR once all filesystems that have -ever had their checksum set to \fBedonr\fR are destroyed. - -FreeBSD does not support the \fBedonr\fR feature. -.RE - -.sp -.ne 2 -.na -\fBembedded_data\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:embedded_data -READ\-ONLY COMPATIBLE no -DEPENDENCIES none -.TE - +to be checksummed. +Thus the produced checksums are unique to a given pool, +preventing hash collision attacks on systems with dedup. +.Pp +.checksum-spiel edonr +.Pp +.Fx does not support the Sy edonr No feature. +. +.feature com.delphix embedded_data no This feature improves the performance and compression ratio of -highly-compressible blocks. Blocks whose contents can compress to 112 bytes +highly-compressible blocks. +Blocks whose contents can compress to 112 bytes or smaller can take advantage of this feature. - +.Pp When this feature is enabled, the contents of highly-compressible blocks are stored in the block "pointer" itself (a misnomer in this case, as it contains -the compressed data, rather than a pointer to its location on disk). Thus -the space of the block (one sector, typically 512 bytes or 4KB) is saved, -and no additional i/o is needed to read and write the data block. - -This feature becomes \fBactive\fR as soon as it is enabled and will -never return to being \fBenabled\fR. -.RE - -.sp -.ne 2 -.na -\fBempty_bpobj\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:empty_bpobj -READ\-ONLY COMPATIBLE yes -DEPENDENCIES none -.TE - +the compressed data, rather than a pointer to its location on disk). +Thus the space of the block (one sector, typically 512B or 4kB) is saved, +and no additional I/O is needed to read and write the data block. +. +\*[instant-never] +. +.feature com.delphix empty_bpobj yes This feature increases the performance of creating and using a large number of snapshots of a single filesystem or volume, and also reduces the disk space required. - +.Pp When there are many snapshots, each snapshot uses many Block Pointer -Objects (bpobj's) to track blocks associated with that snapshot. -However, in common use cases, most of these bpobj's are empty. This -feature allows us to create each bpobj on-demand, thus eliminating the -empty bpobjs. - -This feature is \fBactive\fR while there are any filesystems, volumes, +Objects (bpobjs) to track blocks associated with that snapshot. +However, in common use cases, most of these bpobjs are empty. +This feature allows us to create each bpobj on-demand, +thus eliminating the empty bpobjs. +.Pp +This feature is +.Sy active +while there are any filesystems, volumes, or snapshots which were created after enabling this feature. -.RE - -.sp -.ne 2 -.na -\fBenabled_txg\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:enabled_txg -READ\-ONLY COMPATIBLE yes -DEPENDENCIES none -.TE - -Once this feature is enabled ZFS records the transaction group number -in which new features are enabled. This has no user-visible impact, -but other features may depend on this feature. - -This feature becomes \fBactive\fR as soon as it is enabled and will -never return to being \fBenabled\fB. -.RE - -.sp -.ne 2 -.na -\fBencryption\fR -.ad -.RS 4n -.TS -l l . -GUID com.datto:encryption -READ\-ONLY COMPATIBLE no -DEPENDENCIES bookmark_v2, extensible_dataset -.TE - +. +.feature com.delphix enabled_txg yes +Once this feature is enabled, ZFS records the transaction group number +in which new features are enabled. +This has no user-visible impact, but other features may depend on this feature. +.Pp +This feature becomes +.Sy active + as soon as it is enabled and will +never return to being +.Sy enabled . +. +.feature com.datto encryption no bookmark_v2 extensible_dataset This feature enables the creation and management of natively encrypted datasets. - -This feature becomes \fBactive\fR when an encrypted dataset is created and will -be returned to the \fBenabled\fR state when all datasets that use this feature -are destroyed. -.RE - -.sp -.ne 2 -.na -\fBextensible_dataset\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:extensible_dataset -READ\-ONLY COMPATIBLE no -DEPENDENCIES none -.TE - +.Pp +This feature becomes +.Sy active +when an encrypted dataset is created and will be returned to the +.Sy enabled +state when all datasets that use this feature are destroyed. +. +.feature com.delphix extensible_dataset no This feature allows more flexible use of internal ZFS data structures, and exists for other features to depend on. - -This feature will be \fBactive\fR when the first dependent feature uses it, -and will be returned to the \fBenabled\fR state when all datasets that use -this feature are destroyed. -.RE - -.sp -.ne 2 -.na -\fBfilesystem_limits\fR -.ad -.RS 4n -.TS -l l . -GUID com.joyent:filesystem_limits -READ\-ONLY COMPATIBLE yes -DEPENDENCIES extensible_dataset -.TE - -This feature enables filesystem and snapshot limits. These limits can be used -to control how many filesystems and/or snapshots can be created at the point in -the tree on which the limits are set. - -This feature is \fBactive\fR once either of the limit properties has been -set on a dataset. Once activated the feature is never deactivated. -.RE - -.sp -.ne 2 -.na -\fBhole_birth\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:hole_birth -READ\-ONLY COMPATIBLE no -DEPENDENCIES enabled_txg -.TE - +.Pp +This feature will be +.Sy active +when the first dependent feature uses it, and will be returned to the +.Sy enabled +state when all datasets that use this feature are destroyed. +. +.feature com.joyent filesystem_limits yes extensible_dataset +This feature enables filesystem and snapshot limits. +These limits can be used to control how many filesystems and/or snapshots +can be created at the point in the tree on which the limits are set. +.Pp +This feature is +.Sy active +once either of the limit properties has been set on a dataset. +Once activated the feature is never deactivated. +. +.feature com.delphix hole_birth no enabled_txg This feature has/had bugs, the result of which is that, if you do a -\fBzfs send -i\fR (or \fB-R\fR, since it uses \fB-i\fR) from an affected -dataset, the receiver will not see any checksum or other errors, but the -resulting destination snapshot will not match the source. Its use by -\fBzfs send -i\fR has been disabled by default. See the -\fBsend_holes_without_birth_time\fR module parameter in -zfs-module-parameters(5). - -This feature improves performance of incremental sends (\fBzfs send -i\fR) -and receives for objects with many holes. The most common case of -hole-filled objects is zvols. - -An incremental send stream from snapshot \fBA\fR to snapshot \fBB\fR -contains information about every block that changed between \fBA\fR and -\fBB\fR. Blocks which did not change between those snapshots can be +.Nm zfs Cm send Fl i +.Pq or Fl R , No since it uses Fl i +from an affected dataset, the receiving party will not see any checksum +or other errors, but the resulting destination snapshot +will not match the source. +Its use by +.Nm zfs Cm send Fl i +has been disabled by default +.Pq see Sy send_holes_without_birth_time No in Xr zfs-module-parameters 5 . +.Pp +This feature improves performance of incremental sends +.Pq Nm zfs Cm send Fl i +and receives for objects with many holes. +The most common case of hole-filled objects is zvols. +.Pp +An incremental send stream from snapshot +.Sy A No to snapshot Sy B +contains information about every block that changed between +.Sy A No and Sy B . +Blocks which did not change between those snapshots can be identified and omitted from the stream using a piece of metadata called -the 'block birth time', but birth times are not recorded for holes (blocks -filled only with zeroes). Since holes created after \fBA\fR cannot be -distinguished from holes created before \fBA\fR, information about every -hole in the entire filesystem or zvol is included in the send stream. - -For workloads where holes are rare this is not a problem. However, when -incrementally replicating filesystems or zvols with many holes (for -example a zvol formatted with another filesystem) a lot of time will +the "block birth time", but birth times are not recorded for holes +(blocks filled only with zeroes). +Since holes created after +.Sy A No cannot be distinguished from holes created before Sy A , +information about every hole in the entire filesystem or zvol +is included in the send stream. +.Pp +For workloads where holes are rare this is not a problem. +However, when incrementally replicating filesystems or zvols with many holes +(for example a zvol formatted with another filesystem) a lot of time will be spent sending and receiving unnecessary information about holes that already exist on the receiving side. - -Once the \fBhole_birth\fR feature has been enabled the block birth times -of all new holes will be recorded. Incremental sends between snapshots -created after this feature is enabled will use this new metadata to avoid -sending information about holes that already exist on the receiving side. - -This feature becomes \fBactive\fR as soon as it is enabled and will -never return to being \fBenabled\fB. -.RE - -.sp -.ne 2 -.na -\fBlarge_blocks\fR -.ad -.RS 4n -.TS -l l . -GUID org.open-zfs:large_blocks -READ\-ONLY COMPATIBLE no -DEPENDENCIES extensible_dataset -.TE - -The \fBlarge_block\fR feature allows the record size on a dataset to be -set larger than 128KB. - -This feature becomes \fBactive\fR once a dataset contains a file with -a block size larger than 128KB, and will return to being \fBenabled\fR once all -filesystems that have ever had their recordsize larger than 128KB are destroyed. -.RE - -.sp -.ne 2 -.na -\fBlarge_dnode\fR -.ad -.RS 4n -.TS -l l . -GUID org.zfsonlinux:large_dnode -READ\-ONLY COMPATIBLE no -DEPENDENCIES extensible_dataset -.TE - -The \fBlarge_dnode\fR feature allows the size of dnodes in a dataset to be -set larger than 512B. - -This feature becomes \fBactive\fR once a dataset contains an object with -a dnode larger than 512B, which occurs as a result of setting the -\fBdnodesize\fR dataset property to a value other than \fBlegacy\fR. The -feature will return to being \fBenabled\fR once all filesystems that -have ever contained a dnode larger than 512B are destroyed. Large dnodes -allow more data to be stored in the bonus buffer, thus potentially -improving performance by avoiding the use of spill blocks. -.RE - -.sp -.ne 2 -.na -\fB\fBlivelist\fR\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:livelist -READ\-ONLY COMPATIBLE yes -DEPENDENCIES none -.TE +.Pp +Once the +.Sy hole_birth +feature has been enabled the block birth times +of all new holes will be recorded. +Incremental sends between snapshots created after this feature is enabled +will use this new metadata to avoid sending information about holes that +already exist on the receiving side. +.Pp +\*[instant-never] +. +.feature org.open-zfs large_blocks no extensible_dataset +This feature allows the record size on a dataset to be set larger than 128kB. +.Pp +This feature becomes +.Sy active +once a dataset contains a file with a block size larger than 128kB, +and will return to being +.Sy enabled +once all filesystems that have ever had their recordsize larger than 128kB +are destroyed. +. +.feature org.zfsonlinux large_dnode no extensible_dataset +This feature allows the size of dnodes in a dataset to be set larger than 512B. +. +This feature becomes +.Sy active +once a dataset contains an object with a dnode larger than 512B, +which occurs as a result of setting the +.Sy dnodesize +dataset property to a value other than +.Sy legacy . +The feature will return to being +.Sy enabled +once all filesystems that have ever contained a dnode larger than 512B +are destroyed. +Large dnodes allow more data to be stored in the bonus buffer, +thus potentially improving performance by avoiding the use of spill blocks. +. +.feature com.delphix livelist yes This feature allows clones to be deleted faster than the traditional method when a large number of random/sparse writes have been made to the clone. All blocks allocated and freed after a clone is created are tracked by the the clone's livelist which is referenced during the deletion of the clone. -The feature is activated when a clone is created and remains active until all -clones have been destroyed. -.RE - -.sp -.ne 2 -.na -\fBlog_spacemap\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:log_spacemap -READ\-ONLY COMPATIBLE yes -DEPENDENCIES com.delphix:spacemap_v2 -.TE - +The feature is activated when a clone is created and remains +.Sy active +until all clones have been destroyed. +. +.feature com.delphix log_spacemap yes com.delphix:spacemap_v2 This feature improves performance for heavily-fragmented pools, -especially when workloads are heavy in random-writes. It does so by -logging all the metaslab changes on a single spacemap every TXG +especially when workloads are heavy in random-writes. +It does so by logging all the metaslab changes on a single spacemap every TXG instead of scattering multiple writes to all the metaslab spacemaps. - -This feature becomes \fBactive\fR as soon as it is enabled and will never -return to being \fBenabled\fR. -.RE - -.sp -.ne 2 -.na -\fBlz4_compress\fR -.ad -.RS 4n -.TS -l l . -GUID org.illumos:lz4_compress -READ\-ONLY COMPATIBLE no -DEPENDENCIES none -.TE - -\fBlz4\fR is a high-performance real-time compression algorithm that +.Pp +\*[instant-never] +. +.feature org.illumos lz4_compress no +.Sy lz4 +is a high-performance real-time compression algorithm that features significantly faster compression and decompression as well as a -higher compression ratio than the older \fBlzjb\fR compression. -Typically, \fBlz4\fR compression is approximately 50% faster on -compressible data and 200% faster on incompressible data than -\fBlzjb\fR. It is also approximately 80% faster on decompression, while -giving approximately 10% better compression ratio. - -When the \fBlz4_compress\fR feature is set to \fBenabled\fR, the -administrator can turn on \fBlz4\fR compression on any dataset on the -pool using the zfs(8) command. Please note that doing so will -immediately activate the \fBlz4_compress\fR feature on the underlying -pool using the zfs(8) command. Also, all newly written metadata -will be compressed with \fBlz4\fR algorithm. Since this feature is not -read-only compatible, this operation will render the pool unimportable -on systems without support for the \fBlz4_compress\fR feature. - -This feature becomes \fBactive\fR as soon as it is enabled and will -never return to being \fBenabled\fB. -.RE - -.sp -.ne 2 -.na -\fBmulti_vdev_crash_dump\fR -.ad -.RS 4n -.TS -l l . -GUID com.joyent:multi_vdev_crash_dump -READ\-ONLY COMPATIBLE no -DEPENDENCIES none -.TE - +higher compression ratio than the older +.Sy lzjb +compression. +Typically, +.Sy lz4 +compression is approximately 50% faster on compressible data and 200% faster +on incompressible data than +.Sy lzjb . +It is also approximately 80% faster on decompression, +while giving approximately a 10% better compression ratio. +.Pp +When the +.Sy lz4_compress +feature is set to +.Sy enabled , +the administrator can turn on +.Sy lz4 +compression on any dataset on the pool using the +.Xr zfs-set 8 +command. +All newly written metadata will be compressed with the +.Sy lz4 +algorithm. +.Pp +\*[instant-never] +. +.feature com.joyent multi_vdev_crash_dump no This feature allows a dump device to be configured with a pool comprised -of multiple vdevs. Those vdevs may be arranged in any mirrored or raidz -configuration. - -When the \fBmulti_vdev_crash_dump\fR feature is set to \fBenabled\fR, -the administrator can use the \fBdumpadm\fR(1M) command to configure a -dump device on a pool comprised of multiple vdevs. - -Under FreeBSD and Linux this feature is registered for compatibility but not -used. New pools created under FreeBSD and Linux will have the feature -\fBenabled\fR but will never transition to \fB\fBactive\fR. This functionality -is not required in order to support crash dumps under FreeBSD and Linux. -Existing pools where this feature is \fB\fBactive\fR can be imported. -.RE - -.sp -.ne 2 -.na -\fBobsolete_counts\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:obsolete_counts -READ\-ONLY COMPATIBLE yes -DEPENDENCIES device_removal -.TE - -This feature is an enhancement of device_removal, which will over time -reduce the memory used to track removed devices. When indirect blocks -are freed or remapped, we note that their part of the indirect mapping -is "obsolete", i.e. no longer needed. - -This feature becomes \fBactive\fR when the \fBzpool remove\fR subcommand is -used on a top-level vdev, and will never return to being \fBenabled\fR. -.RE - -.sp -.ne 2 -.na -\fBproject_quota\fR -.ad -.RS 4n -.TS -l l . -GUID org.zfsonlinux:project_quota -READ\-ONLY COMPATIBLE yes -DEPENDENCIES extensible_dataset -.TE - +of multiple vdevs. +Those vdevs may be arranged in any mirrored or raidz configuration. +.Pp +When the +.Sy multi_vdev_crash_dump +feature is set to +.Sy enabled , +the administrator can use +.Xr dumpadm 1M +to configure a dump device on a pool comprised of multiple vdevs. +.Pp +Under +.Fx +and Linux this feature is unused, but registered for compatibility. +New pools created on these systems will have the feature +.Sy enabled +but will never transition to +.Sy active , +as this functionality is not required for crash dump support. +Existing pools where this feature is +.Sy active +can be imported. +. +.feature com.delphix obsolete_counts yes device_removal +This feature is an enhancement of +.Sy device_removal , +which will over time reduce the memory used to track removed devices. +When indirect blocks are freed or remapped, +we note that their part of the indirect mapping is "obsolete" – no longer needed. +.Pp +This feature becomes +.Sy active +when the +.Nm zpool Cm remove +command is used on a top-level vdev, and will never return to being +.Sy enabled . +. +.feature org.zfsonlinux project_quota yes extensible_dataset This feature allows administrators to account the spaces and objects usage information against the project identifier (ID). - -The project ID is new object-based attribute. When upgrading an existing -filesystem, object without project ID attribute will be assigned a zero -project ID. After this feature is enabled, newly created object will inherit -its parent directory's project ID if the parent inherit flag is set (via -\fBchattr +/-P\fR or \fBzfs project [-s|-C]\fR). Otherwise, the new object's -project ID will be set as zero. An object's project ID can be changed at -anytime by the owner (or privileged user) via \fBchattr -p $prjid\fR or -\fBzfs project -p $prjid\fR. - -This feature will become \fBactive\fR as soon as it is enabled and will never -return to being \fBdisabled\fR. Each filesystem will be upgraded automatically -when remounted or when new file is created under that filesystem. The upgrade -can also be triggered on filesystems via `zfs set version=current <pool/fs>`. -The upgrade process runs in the background and may take a while to complete -for the filesystems containing a large number of files. -.RE - -.sp -.ne 2 -.na -\fB\fBredaction_bookmarks\fR\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:redaction_bookmarks -READ\-ONLY COMPATIBLE no -DEPENDENCIES bookmarks, extensible_dataset -.TE - -This feature enables the use of the redacted zfs send. Redacted \fBzfs send\fR -creates redaction bookmarks, which store the list of blocks redacted by the -send that created them. For more information about redacted send, -see \fBzfs\fR(8). - -.RE - -.sp -.ne 2 -.na -\fB\fBredacted_datasets\fR\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:redacted_datasets -READ\-ONLY COMPATIBLE no -DEPENDENCIES extensible_dataset -.TE - -This feature enables the receiving of redacted zfs send streams. Redacted zfs -send streams create redacted datasets when received. These datasets are -missing some of their blocks, and so cannot be safely mounted, and their -contents cannot be safely read. For more information about redacted receive, -see \fBzfs\fR(8). -.RE - -.sp -.ne 2 -.na -\fBresilver_defer\fR -.ad -.RS 4n -.TS -l l . -GUID com.datto:resilver_defer -READ\-ONLY COMPATIBLE yes -DEPENDENCIES none -.TE - -This feature allows zfs to postpone new resilvers if an existing one is already -in progress. Without this feature, any new resilvers will cause the currently +.Pp +The project ID is an object-based attribute. +When upgrading an existing filesystem, +objects without a project ID will be assigned a zero project ID. +When this feature is enabled, newly created objects inherit +their parent directories' project ID if the parent's inherit flag is set +.Pq via Nm chattr Sy [+-]P No or Nm zfs Cm project Fl s Ns | Ns Fl C . +Otherwise, the new object's project ID will be zero. +An object's project ID can be changed at any time by the owner +(or privileged user) via +.Nm chattr Fl p Ar prjid +or +.Nm zfs Cm project Fl p Ar prjid . +.Pp +This feature will become +.Sy active +as soon as it is enabled and will never return to being +.Sy disabled . +\*[remount-upgrade] +. +.feature com.delphix redaction_bookmarks no bookmarks extensible_dataset +This feature enables the use of redacted +.Nm zfs Cm send Ns s , +which create redaction bookmarks storing the list of blocks +redacted by the send that created them. +For more information about redacted sends, see +.Xr zfs-send 8 . +. +.feature com.delphix redacted_datasets no extensible_dataset +This feature enables the receiving of redacted +.Nm zfs Cm send Ns +streams. which create redacted datasets when received. +These datasets are missing some of their blocks, +and so cannot be safely mounted, and their contents cannot be safely read. +For more information about redacted receives, see +.Xr zfs-send 8 . +. +.feature com.datto resilver_defer yes +This feature allows ZFS to postpone new resilvers if an existing one is already +in progress. +Without this feature, any new resilvers will cause the currently running one to be immediately restarted from the beginning. - -This feature becomes \fBactive\fR once a resilver has been deferred, and -returns to being \fBenabled\fR when the deferred resilver begins. -.RE - -.sp -.ne 2 -.na -\fBsha512\fR -.ad -.RS 4n -.TS -l l . -GUID org.illumos:sha512 -READ\-ONLY COMPATIBLE no -DEPENDENCIES extensible_dataset -.TE - +.Pp +This feature becomes +.Sy active +once a resilver has been deferred, and returns to being +.Sy enabled +when the deferred resilver begins. +. +.feature org.illumos sha512 no extensible_dataset This feature enables the use of the SHA-512/256 truncated hash algorithm -(FIPS 180-4) for checksum and dedup. The native 64-bit arithmetic of -SHA-512 provides an approximate 50% performance boost over SHA-256 on -64-bit hardware and is thus a good minimum-change replacement candidate -for systems where hash performance is important, but these systems -cannot for whatever reason utilize the faster \fBskein\fR and -\fBedonr\fR algorithms. - -When the \fBsha512\fR feature is set to \fBenabled\fR, the administrator -can turn on the \fBsha512\fR checksum on any dataset using -\fBzfs set checksum=sha512\fR. See zfs(8). This feature becomes -\fBactive\fR once a \fBchecksum\fR property has been set to \fBsha512\fR, -and will return to being \fBenabled\fR once all filesystems that have -ever had their checksum set to \fBsha512\fR are destroyed. -.RE - -.sp -.ne 2 -.na -\fBskein\fR -.ad -.RS 4n -.TS -l l . -GUID org.illumos:skein -READ\-ONLY COMPATIBLE no -DEPENDENCIES extensible_dataset -.TE - -This feature enables the use of the Skein hash algorithm for checksum -and dedup. Skein is a high-performance secure hash algorithm that was a -finalist in the NIST SHA-3 competition. It provides a very high security -margin and high performance on 64-bit hardware (80% faster than -SHA-256). This implementation also utilizes the new salted checksumming +(FIPS 180-4) for checksum and dedup. +The native 64-bit arithmetic of SHA-512 provides an approximate 50% +performance boost over SHA-256 on 64-bit hardware +and is thus a good minimum-change replacement candidate +for systems where hash performance is important, +but these systems cannot for whatever reason utilize the faster +.Sy skein No and Sy edonr +algorithms. +.Pp +.checksum-spiel sha512 +. +.feature org.illumos skein no extensible_dataset +This feature enables the use of the Skein hash algorithm for checksum and dedup. +Skein is a high-performance secure hash algorithm that was a +finalist in the NIST SHA-3 competition. +It provides a very high security margin and high performance on 64-bit hardware +(80% faster than SHA-256). +This implementation also utilizes the new salted checksumming functionality in ZFS, which means that the checksum is pre-seeded with a secret 256-bit random key (stored on the pool) before being fed the data -block to be checksummed. Thus the produced checksums are unique to a -given pool, preventing hash collision attacks on systems with dedup. - -When the \fBskein\fR feature is set to \fBenabled\fR, the administrator -can turn on the \fBskein\fR checksum on any dataset using -\fBzfs set checksum=skein\fR. See zfs(8). This feature becomes -\fBactive\fR once a \fBchecksum\fR property has been set to \fBskein\fR, -and will return to being \fBenabled\fR once all filesystems that have -ever had their checksum set to \fBskein\fR are destroyed. -.RE - -.sp -.ne 2 -.na -\fBspacemap_histogram\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:spacemap_histogram -READ\-ONLY COMPATIBLE yes -DEPENDENCIES none -.TE - +block to be checksummed. +Thus the produced checksums are unique to a given pool, +preventing hash collision attacks on systems with dedup. +.Pp +.checksum-spiel skein +. +.feature com.delphix spacemap_histogram yes This features allows ZFS to maintain more information about how free space -is organized within the pool. If this feature is \fBenabled\fR, ZFS will -set this feature to \fBactive\fR when a new space map object is created or -an existing space map is upgraded to the new format. Once the feature is -\fBactive\fR, it will remain in that state until the pool is destroyed. -.RE - -.sp -.ne 2 -.na -\fBspacemap_v2\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:spacemap_v2 -READ\-ONLY COMPATIBLE yes -DEPENDENCIES none -.TE - +is organized within the pool. +If this feature is +.Sy enabled , +it will be activated when a new space map object is created, or +an existing space map is upgraded to the new format, +and never returns back to being +.Sy enabled . +. +.feature com.delphix spacemap_v2 yes This feature enables the use of the new space map encoding which consists of two words (instead of one) whenever it is advantageous. The new encoding allows space maps to represent large regions of space more efficiently on-disk while also increasing their maximum addressable offset. - -This feature becomes \fBactive\fR once it is \fBenabled\fR, and never -returns back to being \fBenabled\fR. -.RE - -.sp -.ne 2 -.na -\fBuserobj_accounting\fR -.ad -.RS 4n -.TS -l l . -GUID org.zfsonlinux:userobj_accounting -READ\-ONLY COMPATIBLE yes -DEPENDENCIES extensible_dataset -.TE - +.Pp +This feature becomes +.Sy active +once it is +.Sy enabled , +and never returns back to being +.Sy enabled . +. +.feature org.zfsonlinux userobj_accounting yes extensible_dataset This feature allows administrators to account the object usage information by user and group. - -This feature becomes \fBactive\fR as soon as it is enabled and will never -return to being \fBenabled\fR. Each filesystem will be upgraded automatically -when remounted, or when new files are created under that filesystem. -The upgrade can also be started manually on filesystems by running -`zfs set version=current <pool/fs>`. The upgrade process runs in the background -and may take a while to complete for filesystems containing a large number of -files. -.RE - -.sp -.ne 2 -.na -\fBzpool_checkpoint\fR -.ad -.RS 4n -.TS -l l . -GUID com.delphix:zpool_checkpoint -READ\-ONLY COMPATIBLE yes -DEPENDENCIES none -.TE - -This feature enables the \fBzpool checkpoint\fR subcommand that can -checkpoint the state of the pool at the time it was issued and later -rewind back to it or discard it. - -This feature becomes \fBactive\fR when the \fBzpool checkpoint\fR subcommand -is used to checkpoint the pool. -The feature will only return back to being \fBenabled\fR when the pool -is rewound or the checkpoint has been discarded. -.RE - -.sp -.ne 2 -.na -\fBzstd_compress\fR -.ad -.RS 4n -.TS -l l . -GUID org.freebsd:zstd_compress -READ\-ONLY COMPATIBLE no -DEPENDENCIES extensible_dataset -.TE - -\fBzstd\fR is a high-performance compression algorithm that features a -combination of high compression ratios and high speed. Compared to \fBgzip\fR, -\fBzstd\fR offers slightly better compression at much higher speeds. Compared -to \fBlz4\fR, \fBzstd\fR offers much better compression while being only -modestly slower. Typically, \fBzstd\fR compression speed ranges from 250 to 500 -MB/s per thread and decompression speed is over 1 GB/s per thread. - -When the \fBzstd\fR feature is set to \fBenabled\fR, the administrator can turn -on \fBzstd\fR compression of any dataset by running -`zfs set compress=zstd <pool/fs>`. - -This feature becomes \fBactive\fR once a \fBcompress\fR property has been set to -\fBzstd\fR, and will return to being \fBenabled\fR once all filesystems that -have ever had their compress property set to \fBzstd\fR are destroyed. -.RE - -.SH "SEE ALSO" -zpool(8) +.Pp +\*[instant-never] +\*[remount-upgrade] +. +.feature com.delphix zpool_checkpoint yes +This feature enables the +.Nm zpool Cm checkpoint +command that can checkpoint the state of the pool +at the time it was issued and later rewind back to it or discard it. +.Pp +This feature becomes +.Sy active +when the +.Nm zpool Cm checkpoint +command is used to checkpoint the pool. +The feature will only return back to being +.Sy enabled +when the pool is rewound or the checkpoint has been discarded. +. +.feature org.freebsd zstd_compress no extensible_dataset +.Sy zstd +is a high-performance compression algorithm that features a +combination of high compression ratios and high speed. +Compared to +.Sy gzip , +.Sy zstd +offers slightly better compression at much higher speeds. +Compared to +.Sy lz4 , +.Sy zstd +offers much better compression while being only modestly slower. +Typically, +.Sy zstd +compression speed ranges from 250 to 500 MB/s per thread +and decompression speed is over 1 GB/s per thread. +.Pp +When the +.Sy zstd +feature is set to +.Sy enabled , +the administrator can turn on +.Sy zstd +compression of any dataset using +.Nm zfs Cm set Sy compress Ns = Ns Sy zstd Ar dset +.Po see Xr zfs-set 8 Pc . +This feature becomes +.Sy active +once a +.Sy compress +property has been set to +.Sy zstd , +and will return to being +.Sy enabled +once all filesystems that have ever had their +.Sy compress +property set to +.Sy zstd +are destroyed. +.El +. +.Sh SEE ALSO +.Xr zpool 8 |