2 .\" Copyright (c) 2012, 2018 by Delphix. All rights reserved.
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17 .\" Copyright (c) 2019, Klara Inc.
18 .\" Copyright (c) 2019, Allan Jude
19 .TH ZPOOL-FEATURES 5 "Jun 8, 2018"
21 zpool\-features \- ZFS pool feature descriptions
25 ZFS pool on\-disk format versions are specified via "features" which replace
26 the old on\-disk format numbers (the last supported on\-disk format number is
27 28). To enable a feature on a pool use the \fBupgrade\fR subcommand of the
28 zpool(8) command, or set the \fBfeature@\fR\fIfeature_name\fR property
32 The pool format does not affect file system version compatibility or the ability
33 to send file systems between pools.
36 Since most features can be enabled independently of each other the on\-disk
37 format of the pool is specified by the set of all features marked as
38 \fBactive\fR on the pool. If the pool was created by another software version
39 this set may include unsupported features.
40 .SS "Identifying features"
43 Every feature has a GUID of the form \fIcom.example:feature_name\fR. The
44 reversed DNS name ensures that the feature's GUID is unique across all ZFS
45 implementations. When unsupported features are encountered on a pool they will
46 be identified by their GUIDs. Refer to the documentation for the ZFS
47 implementation that created the pool for information about those features.
50 Each supported feature also has a short name. By convention a feature's short
51 name is the portion of its GUID which follows the ':' (e.g.
52 \fIcom.example:feature_name\fR would have the short name \fIfeature_name\fR),
53 however a feature's short name may differ across ZFS implementations if
54 following the convention would result in name conflicts.
58 Features can be in one of three states:
65 This feature's on\-disk format changes are in effect on the pool. Support for
66 this feature is required to import the pool in read\-write mode. If this
67 feature is not read-only compatible, support is also required to import the pool
68 in read\-only mode (see "Read\-only compatibility").
77 An administrator has marked this feature as enabled on the pool, but the
78 feature's on\-disk format changes have not been made yet. The pool can still be
79 imported by software that does not support this feature, but changes may be made
80 to the on\-disk format at any time which will move the feature to the
81 \fBactive\fR state. Some features may support returning to the \fBenabled\fR
82 state after becoming \fBactive\fR. See feature\-specific documentation for
92 This feature's on\-disk format changes have not been made and will not be made
93 unless an administrator moves the feature to the \fBenabled\fR state. Features
94 cannot be disabled once they have been enabled.
99 The state of supported features is exposed through pool properties of the form
100 \fIfeature@short_name\fR.
101 .SS "Read\-only compatibility"
104 Some features may make on\-disk format changes that do not interfere with other
105 software's ability to read from the pool. These features are referred to as
106 "read\-only compatible". If all unsupported features on a pool are read\-only
107 compatible, the pool can be imported in read\-only mode by setting the
108 \fBreadonly\fR property during import (see zpool(8) for details on
110 .SS "Unsupported features"
113 For each unsupported feature enabled on an imported pool a pool property
114 named \fIunsupported@feature_name\fR will indicate why the import was allowed
115 despite the unsupported feature. Possible values for this property are:
123 The feature is in the \fBenabled\fR state and therefore the pool's on\-disk
124 format is still compatible with software that does not support this feature.
133 The feature is read\-only compatible and the pool has been imported in
137 .SS "Feature dependencies"
140 Some features depend on other features being enabled in order to function
141 properly. Enabling a feature will automatically enable any features it
146 The following features are supported on this system:
151 \fBallocation_classes\fR
156 GUID org.zfsonlinux:allocation_classes
157 READ\-ONLY COMPATIBLE yes
161 This feature enables support for separate allocation classes.
163 This feature becomes \fBactive\fR when a dedicated allocation class vdev
164 (dedup or special) is created with the \fBzpool create\fR or \fBzpool add\fR
165 subcommands. With device removal, it can be returned to the \fBenabled\fR
166 state if all the dedicated allocation class vdevs are removed.
177 GUID com.delphix:async_destroy
178 READ\-ONLY COMPATIBLE yes
182 Destroying a file system requires traversing all of its data in order to
183 return its used space to the pool. Without \fBasync_destroy\fR the file system
184 is not fully removed until all space has been reclaimed. If the destroy
185 operation is interrupted by a reboot or power outage the next attempt to open
186 the pool will need to complete the destroy operation synchronously.
188 When \fBasync_destroy\fR is enabled the file system's data will be reclaimed
189 by a background process, allowing the destroy operation to complete without
190 traversing the entire file system. The background process is able to resume
191 interrupted destroys after the pool has been opened, eliminating the need
192 to finish interrupted destroys as part of the open operation. The amount
193 of space remaining to be reclaimed by the background process is available
194 through the \fBfreeing\fR property.
196 This feature is only \fBactive\fR while \fBfreeing\fR is non\-zero.
207 GUID com.delphix:bookmarks
208 READ\-ONLY COMPATIBLE yes
209 DEPENDENCIES extensible_dataset
212 This feature enables use of the \fBzfs bookmark\fR subcommand.
214 This feature is \fBactive\fR while any bookmarks exist in the pool.
215 All bookmarks in the pool can be listed by running
216 \fBzfs list -t bookmark -r \fIpoolname\fR\fR.
227 GUID com.datto:bookmark_v2
228 READ\-ONLY COMPATIBLE no
229 DEPENDENCIES bookmark, extensible_dataset
232 This feature enables the creation and management of larger bookmarks which are
233 needed for other features in ZFS.
235 This feature becomes \fBactive\fR when a v2 bookmark is created and will be
236 returned to the \fBenabled\fR state when all v2 bookmarks are destroyed.
242 \fBbookmark_written\fR
247 GUID com.delphix:bookmark_written
248 READ\-ONLY COMPATIBLE no
249 DEPENDENCIES bookmark, extensible_dataset, bookmark_v2
252 This feature enables additional bookmark accounting fields, enabling the
253 written#<bookmark> property (space written since a bookmark) and estimates of
254 send stream sizes for incrementals from bookmarks.
256 This feature becomes \fBactive\fR when a bookmark is created and will be
257 returned to the \fBenabled\fR state when all bookmarks with these fields are destroyed.
268 GUID org.openzfs:device_rebuild
269 READ\-ONLY COMPATIBLE yes
273 This feature enables the ability for the \fBzpool attach\fR and \fBzpool
274 replace\fR subcommands to perform sequential reconstruction (instead of
275 healing reconstruction) when resilvering.
277 Sequential reconstruction resilvers a device in LBA order without immediately
278 verifying the checksums. Once complete a scrub is started which then verifies
279 the checksums. This approach allows full redundancy to be restored to the pool
280 in the minimum amount of time. This two phase approach will take longer than a
281 healing resilver when the time to verify the checksums is included. However,
282 unless there is additional pool damage no checksum errors should be reported
283 by the scrub. This feature is incompatible with raidz configurations.
285 This feature becomes \fBactive\fR while a sequential resilver is in progress,
286 and returns to \fBenabled\fR when the resilver completes.
297 GUID com.delphix:device_removal
298 READ\-ONLY COMPATIBLE no
302 This feature enables the \fBzpool remove\fR subcommand to remove top-level
303 vdevs, evacuating them to reduce the total size of the pool.
305 This feature becomes \fBactive\fR when the \fBzpool remove\fR subcommand is used
306 on a top-level vdev, and will never return to being \fBenabled\fR.
317 GUID org.illumos:edonr
318 READ\-ONLY COMPATIBLE no
319 DEPENDENCIES extensible_dataset
322 This feature enables the use of the Edon-R hash algorithm for checksum,
323 including for nopwrite (if compression is also enabled, an overwrite of
324 a block whose checksum matches the data being written will be ignored).
325 In an abundance of caution, Edon-R requires verification when used with
326 dedup: \fBzfs set dedup=edonr,verify\fR. See \fBzfs\fR(8).
328 Edon-R is a very high-performance hash algorithm that was part
329 of the NIST SHA-3 competition. It provides extremely high hash
330 performance (over 350% faster than SHA-256), but was not selected
331 because of its unsuitability as a general purpose secure hash algorithm.
332 This implementation utilizes the new salted checksumming functionality
333 in ZFS, which means that the checksum is pre-seeded with a secret
334 256-bit random key (stored on the pool) before being fed the data block
335 to be checksummed. Thus the produced checksums are unique to a given
338 When the \fBedonr\fR feature is set to \fBenabled\fR, the administrator
339 can turn on the \fBedonr\fR checksum on any dataset using the
340 \fBzfs set checksum=edonr\fR. See zfs(8). This feature becomes
341 \fBactive\fR once a \fBchecksum\fR property has been set to \fBedonr\fR,
342 and will return to being \fBenabled\fR once all filesystems that have
343 ever had their checksum set to \fBedonr\fR are destroyed.
345 FreeBSD does not support the \fBedonr\fR feature.
356 GUID com.delphix:embedded_data
357 READ\-ONLY COMPATIBLE no
361 This feature improves the performance and compression ratio of
362 highly-compressible blocks. Blocks whose contents can compress to 112 bytes
363 or smaller can take advantage of this feature.
365 When this feature is enabled, the contents of highly-compressible blocks are
366 stored in the block "pointer" itself (a misnomer in this case, as it contains
367 the compressed data, rather than a pointer to its location on disk). Thus
368 the space of the block (one sector, typically 512 bytes or 4KB) is saved,
369 and no additional i/o is needed to read and write the data block.
371 This feature becomes \fBactive\fR as soon as it is enabled and will
372 never return to being \fBenabled\fR.
383 GUID com.delphix:empty_bpobj
384 READ\-ONLY COMPATIBLE yes
388 This feature increases the performance of creating and using a large
389 number of snapshots of a single filesystem or volume, and also reduces
390 the disk space required.
392 When there are many snapshots, each snapshot uses many Block Pointer
393 Objects (bpobj's) to track blocks associated with that snapshot.
394 However, in common use cases, most of these bpobj's are empty. This
395 feature allows us to create each bpobj on-demand, thus eliminating the
398 This feature is \fBactive\fR while there are any filesystems, volumes,
399 or snapshots which were created after enabling this feature.
410 GUID com.delphix:enabled_txg
411 READ\-ONLY COMPATIBLE yes
415 Once this feature is enabled ZFS records the transaction group number
416 in which new features are enabled. This has no user-visible impact,
417 but other features may depend on this feature.
419 This feature becomes \fBactive\fR as soon as it is enabled and will
420 never return to being \fBenabled\fB.
431 GUID com.datto:encryption
432 READ\-ONLY COMPATIBLE no
433 DEPENDENCIES bookmark_v2, extensible_dataset
436 This feature enables the creation and management of natively encrypted datasets.
438 This feature becomes \fBactive\fR when an encrypted dataset is created and will
439 be returned to the \fBenabled\fR state when all datasets that use this feature
446 \fBextensible_dataset\fR
451 GUID com.delphix:extensible_dataset
452 READ\-ONLY COMPATIBLE no
456 This feature allows more flexible use of internal ZFS data structures,
457 and exists for other features to depend on.
459 This feature will be \fBactive\fR when the first dependent feature uses it,
460 and will be returned to the \fBenabled\fR state when all datasets that use
461 this feature are destroyed.
467 \fBfilesystem_limits\fR
472 GUID com.joyent:filesystem_limits
473 READ\-ONLY COMPATIBLE yes
474 DEPENDENCIES extensible_dataset
477 This feature enables filesystem and snapshot limits. These limits can be used
478 to control how many filesystems and/or snapshots can be created at the point in
479 the tree on which the limits are set.
481 This feature is \fBactive\fR once either of the limit properties has been
482 set on a dataset. Once activated the feature is never deactivated.
493 GUID com.delphix:hole_birth
494 READ\-ONLY COMPATIBLE no
495 DEPENDENCIES enabled_txg
498 This feature has/had bugs, the result of which is that, if you do a
499 \fBzfs send -i\fR (or \fB-R\fR, since it uses \fB-i\fR) from an affected
500 dataset, the receiver will not see any checksum or other errors, but the
501 resulting destination snapshot will not match the source. Its use by
502 \fBzfs send -i\fR has been disabled by default. See the
503 \fBsend_holes_without_birth_time\fR module parameter in
504 zfs-module-parameters(5).
506 This feature improves performance of incremental sends (\fBzfs send -i\fR)
507 and receives for objects with many holes. The most common case of
508 hole-filled objects is zvols.
510 An incremental send stream from snapshot \fBA\fR to snapshot \fBB\fR
511 contains information about every block that changed between \fBA\fR and
512 \fBB\fR. Blocks which did not change between those snapshots can be
513 identified and omitted from the stream using a piece of metadata called
514 the 'block birth time', but birth times are not recorded for holes (blocks
515 filled only with zeroes). Since holes created after \fBA\fR cannot be
516 distinguished from holes created before \fBA\fR, information about every
517 hole in the entire filesystem or zvol is included in the send stream.
519 For workloads where holes are rare this is not a problem. However, when
520 incrementally replicating filesystems or zvols with many holes (for
521 example a zvol formatted with another filesystem) a lot of time will
522 be spent sending and receiving unnecessary information about holes that
523 already exist on the receiving side.
525 Once the \fBhole_birth\fR feature has been enabled the block birth times
526 of all new holes will be recorded. Incremental sends between snapshots
527 created after this feature is enabled will use this new metadata to avoid
528 sending information about holes that already exist on the receiving side.
530 This feature becomes \fBactive\fR as soon as it is enabled and will
531 never return to being \fBenabled\fB.
542 GUID org.open-zfs:large_blocks
543 READ\-ONLY COMPATIBLE no
544 DEPENDENCIES extensible_dataset
547 The \fBlarge_block\fR feature allows the record size on a dataset to be
548 set larger than 128KB.
550 This feature becomes \fBactive\fR once a dataset contains a file with
551 a block size larger than 128KB, and will return to being \fBenabled\fR once all
552 filesystems that have ever had their recordsize larger than 128KB are destroyed.
563 GUID org.zfsonlinux:large_dnode
564 READ\-ONLY COMPATIBLE no
565 DEPENDENCIES extensible_dataset
568 The \fBlarge_dnode\fR feature allows the size of dnodes in a dataset to be
569 set larger than 512B.
571 This feature becomes \fBactive\fR once a dataset contains an object with
572 a dnode larger than 512B, which occurs as a result of setting the
573 \fBdnodesize\fR dataset property to a value other than \fBlegacy\fR. The
574 feature will return to being \fBenabled\fR once all filesystems that
575 have ever contained a dnode larger than 512B are destroyed. Large dnodes
576 allow more data to be stored in the bonus buffer, thus potentially
577 improving performance by avoiding the use of spill blocks.
588 GUID com.delphix:livelist
589 READ\-ONLY COMPATIBLE yes
592 This feature allows clones to be deleted faster than the traditional method
593 when a large number of random/sparse writes have been made to the clone.
594 All blocks allocated and freed after a clone is created are tracked by the
595 the clone's livelist which is referenced during the deletion of the clone.
596 The feature is activated when a clone is created and remains active until all
597 clones have been destroyed.
608 GUID com.delphix:log_spacemap
609 READ\-ONLY COMPATIBLE yes
610 DEPENDENCIES com.delphix:spacemap_v2
613 This feature improves performance for heavily-fragmented pools,
614 especially when workloads are heavy in random-writes. It does so by
615 logging all the metaslab changes on a single spacemap every TXG
616 instead of scattering multiple writes to all the metaslab spacemaps.
618 This feature becomes \fBactive\fR as soon as it is enabled and will never
619 return to being \fBenabled\fR.
630 GUID org.illumos:lz4_compress
631 READ\-ONLY COMPATIBLE no
635 \fBlz4\fR is a high-performance real-time compression algorithm that
636 features significantly faster compression and decompression as well as a
637 higher compression ratio than the older \fBlzjb\fR compression.
638 Typically, \fBlz4\fR compression is approximately 50% faster on
639 compressible data and 200% faster on incompressible data than
640 \fBlzjb\fR. It is also approximately 80% faster on decompression, while
641 giving approximately 10% better compression ratio.
643 When the \fBlz4_compress\fR feature is set to \fBenabled\fR, the
644 administrator can turn on \fBlz4\fR compression on any dataset on the
645 pool using the zfs(8) command. Please note that doing so will
646 immediately activate the \fBlz4_compress\fR feature on the underlying
647 pool using the zfs(8) command. Also, all newly written metadata
648 will be compressed with \fBlz4\fR algorithm. Since this feature is not
649 read-only compatible, this operation will render the pool unimportable
650 on systems without support for the \fBlz4_compress\fR feature.
652 Booting off of \fBlz4\fR-compressed root pools is supported.
654 This feature becomes \fBactive\fR as soon as it is enabled and will
655 never return to being \fBenabled\fB.
661 \fBmulti_vdev_crash_dump\fR
666 GUID com.joyent:multi_vdev_crash_dump
667 READ\-ONLY COMPATIBLE no
671 This feature allows a dump device to be configured with a pool comprised
672 of multiple vdevs. Those vdevs may be arranged in any mirrored or raidz
675 When the \fBmulti_vdev_crash_dump\fR feature is set to \fBenabled\fR,
676 the administrator can use the \fBdumpadm\fR(1M) command to configure a
677 dump device on a pool comprised of multiple vdevs.
679 Under Linux this feature is registered for compatibility but not used.
680 New pools created under Linux will have the feature \fBenabled\fR but
681 will never transition to \fB\fBactive\fR. This functionality is not
682 required in order to support crash dumps under Linux. Existing pools
683 where this feature is \fB\fBactive\fR can be imported.
689 \fBobsolete_counts\fR
694 GUID com.delphix:obsolete_counts
695 READ\-ONLY COMPATIBLE yes
696 DEPENDENCIES device_removal
699 This feature is an enhancement of device_removal, which will over time
700 reduce the memory used to track removed devices. When indirect blocks
701 are freed or remapped, we note that their part of the indirect mapping
702 is "obsolete", i.e. no longer needed.
704 This feature becomes \fBactive\fR when the \fBzpool remove\fR subcommand is
705 used on a top-level vdev, and will never return to being \fBenabled\fR.
716 GUID org.zfsonlinux:project_quota
717 READ\-ONLY COMPATIBLE yes
718 DEPENDENCIES extensible_dataset
721 This feature allows administrators to account the spaces and objects usage
722 information against the project identifier (ID).
724 The project ID is new object-based attribute. When upgrading an existing
725 filesystem, object without project ID attribute will be assigned a zero
726 project ID. After this feature is enabled, newly created object will inherit
727 its parent directory's project ID if the parent inherit flag is set (via
728 \fBchattr +/-P\fR or \fBzfs project [-s|-C]\fR). Otherwise, the new object's
729 project ID will be set as zero. An object's project ID can be changed at
730 anytime by the owner (or privileged user) via \fBchattr -p $prjid\fR or
731 \fBzfs project -p $prjid\fR.
733 This feature will become \fBactive\fR as soon as it is enabled and will never
734 return to being \fBdisabled\fR. Each filesystem will be upgraded automatically
735 when remounted or when new file is created under that filesystem. The upgrade
736 can also be triggered on filesystems via `zfs set version=current <pool/fs>`.
737 The upgrade process runs in the background and may take a while to complete
738 for the filesystems containing a large number of files.
744 \fB\fBredaction_bookmarks\fR\fR
749 GUID com.delphix:redaction_bookmarks
750 READ\-ONLY COMPATIBLE no
751 DEPENDENCIES bookmarks, extensible_dataset
754 This feature enables the use of the redacted zfs send. Redacted \fBzfs send\fR
755 creates redaction bookmarks, which store the list of blocks redacted by the
756 send that created them. For more information about redacted send,
764 \fB\fBredacted_datasets\fR\fR
769 GUID com.delphix:redacted_datasets
770 READ\-ONLY COMPATIBLE no
771 DEPENDENCIES extensible_dataset
774 This feature enables the receiving of redacted zfs send streams. Redacted zfs
775 send streams create redacted datasets when received. These datasets are
776 missing some of their blocks, and so cannot be safely mounted, and their
777 contents cannot be safely read. For more information about redacted receive,
789 GUID com.datto:resilver_defer
790 READ\-ONLY COMPATIBLE yes
794 This feature allows zfs to postpone new resilvers if an existing one is already
795 in progress. Without this feature, any new resilvers will cause the currently
796 running one to be immediately restarted from the beginning.
798 This feature becomes \fBactive\fR once a resilver has been deferred, and
799 returns to being \fBenabled\fR when the deferred resilver begins.
810 GUID org.illumos:sha512
811 READ\-ONLY COMPATIBLE no
812 DEPENDENCIES extensible_dataset
815 This feature enables the use of the SHA-512/256 truncated hash algorithm
816 (FIPS 180-4) for checksum and dedup. The native 64-bit arithmetic of
817 SHA-512 provides an approximate 50% performance boost over SHA-256 on
818 64-bit hardware and is thus a good minimum-change replacement candidate
819 for systems where hash performance is important, but these systems
820 cannot for whatever reason utilize the faster \fBskein\fR and
821 \fBedonr\fR algorithms.
823 When the \fBsha512\fR feature is set to \fBenabled\fR, the administrator
824 can turn on the \fBsha512\fR checksum on any dataset using
825 \fBzfs set checksum=sha512\fR. See zfs(8). This feature becomes
826 \fBactive\fR once a \fBchecksum\fR property has been set to \fBsha512\fR,
827 and will return to being \fBenabled\fR once all filesystems that have
828 ever had their checksum set to \fBsha512\fR are destroyed.
839 GUID org.illumos:skein
840 READ\-ONLY COMPATIBLE no
841 DEPENDENCIES extensible_dataset
844 This feature enables the use of the Skein hash algorithm for checksum
845 and dedup. Skein is a high-performance secure hash algorithm that was a
846 finalist in the NIST SHA-3 competition. It provides a very high security
847 margin and high performance on 64-bit hardware (80% faster than
848 SHA-256). This implementation also utilizes the new salted checksumming
849 functionality in ZFS, which means that the checksum is pre-seeded with a
850 secret 256-bit random key (stored on the pool) before being fed the data
851 block to be checksummed. Thus the produced checksums are unique to a
852 given pool, preventing hash collision attacks on systems with dedup.
854 When the \fBskein\fR feature is set to \fBenabled\fR, the administrator
855 can turn on the \fBskein\fR checksum on any dataset using
856 \fBzfs set checksum=skein\fR. See zfs(8). This feature becomes
857 \fBactive\fR once a \fBchecksum\fR property has been set to \fBskein\fR,
858 and will return to being \fBenabled\fR once all filesystems that have
859 ever had their checksum set to \fBskein\fR are destroyed.
865 \fBspacemap_histogram\fR
870 GUID com.delphix:spacemap_histogram
871 READ\-ONLY COMPATIBLE yes
875 This features allows ZFS to maintain more information about how free space
876 is organized within the pool. If this feature is \fBenabled\fR, ZFS will
877 set this feature to \fBactive\fR when a new space map object is created or
878 an existing space map is upgraded to the new format. Once the feature is
879 \fBactive\fR, it will remain in that state until the pool is destroyed.
890 GUID com.delphix:spacemap_v2
891 READ\-ONLY COMPATIBLE yes
895 This feature enables the use of the new space map encoding which
896 consists of two words (instead of one) whenever it is advantageous.
897 The new encoding allows space maps to represent large regions of
898 space more efficiently on-disk while also increasing their maximum
901 This feature becomes \fBactive\fR once it is \fBenabled\fR, and never
902 returns back to being \fBenabled\fR.
908 \fBuserobj_accounting\fR
913 GUID org.zfsonlinux:userobj_accounting
914 READ\-ONLY COMPATIBLE yes
915 DEPENDENCIES extensible_dataset
918 This feature allows administrators to account the object usage information
921 This feature becomes \fBactive\fR as soon as it is enabled and will never
922 return to being \fBenabled\fR. Each filesystem will be upgraded automatically
923 when remounted, or when new files are created under that filesystem.
924 The upgrade can also be started manually on filesystems by running
925 `zfs set version=current <pool/fs>`. The upgrade process runs in the background
926 and may take a while to complete for filesystems containing a large number of
933 \fBzpool_checkpoint\fR
938 GUID com.delphix:zpool_checkpoint
939 READ\-ONLY COMPATIBLE yes
943 This feature enables the \fBzpool checkpoint\fR subcommand that can
944 checkpoint the state of the pool at the time it was issued and later
945 rewind back to it or discard it.
947 This feature becomes \fBactive\fR when the \fBzpool checkpoint\fR subcommand
948 is used to checkpoint the pool.
949 The feature will only return back to being \fBenabled\fR when the pool
950 is rewound or the checkpoint has been discarded.
961 GUID org.freebsd:zstd_compress
962 READ\-ONLY COMPATIBLE no
963 DEPENDENCIES extensible_dataset
966 \fBzstd\fR is a high-performance compression algorithm that features a
967 combination of high compression ratios and high speed. Compared to \fBgzip\fR,
968 \fBzstd\fR offers slighty better compression at much higher speeds. Compared
969 to \fBlz4\fR, \fBzstd\fR offers much better compression while being only
970 modestly slower. Typically, \fBzstd\fR compression speed ranges from 250 to 500
971 MB/s per thread and decompression speed is over 1 GB/s per thread.
973 When the \fBzstd\fR feature is set to \fBenabled\fR, the administrator can turn
974 on \fBzstd\fR compression of any dataset by running
975 `zfs set compress=zstd <pool/fs>`.
977 This feature becomes \fBactive\fR once a \fBcompress\fR property has been set to
978 \fBzstd\fR, and will return to being \fBenabled\fR once all filesystems that
979 have ever had their compress property set to \fBzstd\fR are destroyed.
981 Booting off of \fBzstd\fR-compressed root pools is not yet supported.
projects / FreeBSD / FreeBSD.git / blob