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a1d477c24c
OpenZFS 7614 - zfs device evacuation/removal
OpenZFS 9064 - remove_mirror should wait for device removal to complete
This project allows top-level vdevs to be removed from the storage pool
with "zpool remove", reducing the total amount of storage in the pool.
This operation copies all allocated regions of the device to be removed
onto other devices, recording the mapping from old to new location.
After the removal is complete, read and free operations to the removed
(now "indirect") vdev must be remapped and performed at the new location
on disk. The indirect mapping table is kept in memory whenever the pool
is loaded, so there is minimal performance overhead when doing operations
on the indirect vdev.
The size of the in-memory mapping table will be reduced when its entries
become "obsolete" because they are no longer used by any block pointers
in the pool. An entry becomes obsolete when all the blocks that use
it are freed. An entry can also become obsolete when all the snapshots
that reference it are deleted, and the block pointers that reference it
have been "remapped" in all filesystems/zvols (and clones). Whenever an
indirect block is written, all the block pointers in it will be "remapped"
to their new (concrete) locations if possible. This process can be
accelerated by using the "zfs remap" command to proactively rewrite all
indirect blocks that reference indirect (removed) vdevs.
Note that when a device is removed, we do not verify the checksum of
the data that is copied. This makes the process much faster, but if it
were used on redundant vdevs (i.e. mirror or raidz vdevs), it would be
possible to copy the wrong data, when we have the correct data on e.g.
the other side of the mirror.
At the moment, only mirrors and simple top-level vdevs can be removed
and no removal is allowed if any of the top-level vdevs are raidz.
Porting Notes:
* Avoid zero-sized kmem_alloc() in vdev_compact_children().
The device evacuation code adds a dependency that
vdev_compact_children() be able to properly empty the vdev_child
array by setting it to NULL and zeroing vdev_children. Under Linux,
kmem_alloc() and related functions return a sentinel pointer rather
than NULL for zero-sized allocations.
* Remove comment regarding "mpt" driver where zfs_remove_max_segment
is initialized to SPA_MAXBLOCKSIZE.
Change zfs_condense_indirect_commit_entry_delay_ticks to
zfs_condense_indirect_commit_entry_delay_ms for consistency with
most other tunables in which delays are specified in ms.
* ZTS changes:
Use set_tunable rather than mdb
Use zpool sync as appropriate
Use sync_pool instead of sync
Kill jobs during test_removal_with_operation to allow unmount/export
Don't add non-disk names such as "mirror" or "raidz" to $DISKS
Use $TEST_BASE_DIR instead of /tmp
Increase HZ from 100 to 1000 which is more common on Linux
removal_multiple_indirection.ksh
Reduce iterations in order to not time out on the code
coverage builders.
removal_resume_export:
Functionally, the test case is correct but there exists a race
where the kernel thread hasn't been fully started yet and is
not visible. Wait for up to 1 second for the removal thread
to be started before giving up on it. Also, increase the
amount of data copied in order that the removal not finish
before the export has a chance to fail.
* MMP compatibility, the concept of concrete versus non-concrete devices
has slightly changed the semantics of vdev_writeable(). Update
mmp_random_leaf_impl() accordingly.
* Updated dbuf_remap() to handle the org.zfsonlinux:large_dnode pool
feature which is not supported by OpenZFS.
* Added support for new vdev removal tracepoints.
* Test cases removal_with_zdb and removal_condense_export have been
intentionally disabled. When run manually they pass as intended,
but when running in the automated test environment they produce
unreliable results on the latest Fedora release.
They may work better once the upstream pool import refectoring is
merged into ZoL at which point they will be re-enabled.
Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Alex Reece <alex@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Richard Laager <rlaager@wiktel.com>
Reviewed by: Tim Chase <tim@chase2k.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Garrett D'Amore <garrett@damore.org>
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Tim Chase <tim@chase2k.com>
OpenZFS-issue: https://www.illumos.org/issues/7614
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f539f1eb
Closes #6900
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'\" te
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.\" Copyright (c) 2013, 2016 by Delphix. All rights reserved.
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.\" Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
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.\" Copyright (c) 2014, Joyent, Inc. All rights reserved.
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.\" The contents of this file are subject to the terms of the Common Development
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.\" and Distribution License (the "License"). You may not use this file except
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.\" in compliance with the License. You can obtain a copy of the license at
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.\" usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.
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.\"
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.\" See the License for the specific language governing permissions and
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.\" limitations under the License. When distributing Covered Code, include this
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.\" CDDL HEADER in each file and include the License file at
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.\" usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this
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.\" CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your
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.\" own identifying information:
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.\" Portions Copyright [yyyy] [name of copyright owner]
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.TH ZPOOL-FEATURES 5 "Aug 27, 2013"
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.SH NAME
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zpool\-features \- ZFS pool feature descriptions
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.SH DESCRIPTION
|
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.sp
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.LP
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ZFS pool on\-disk format versions are specified via "features" which replace
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the old on\-disk format numbers (the last supported on\-disk format number is
|
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28). To enable a feature on a pool use the \fBupgrade\fR subcommand of the
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\fBzpool\fR(8) command, or set the \fBfeature@\fR\fIfeature_name\fR property
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to \fBenabled\fR.
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.sp
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.LP
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|
The pool format does not affect file system version compatibility or the ability
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to send file systems between pools.
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.sp
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.LP
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|
Since most features can be enabled independently of each other the on\-disk
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|
format of the pool is specified by the set of all features marked as
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\fBactive\fR on the pool. If the pool was created by another software version
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this set may include unsupported features.
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.SS "Identifying features"
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|
.sp
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|
.LP
|
|
Every feature has a guid of the form \fIcom.example:feature_name\fR. The reverse
|
|
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.
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|
.sp
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|
.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.
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|
\fIcom.example:feature_name\fR would have the short name \fIfeature_name\fR),
|
|
however a feature's short name may differ across ZFS implementations if
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|
following the convention would result in name conflicts.
|
|
.SS "Feature states"
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|
.sp
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|
.LP
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|
Features can be in one of three states:
|
|
.sp
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.ne 2
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|
.na
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|
\fB\fBactive\fR\fR
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|
.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
|
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.ne 2
|
|
.na
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|
\fB\fBenabled\fR\fR
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|
.ad
|
|
.RS 12n
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|
An administrator has marked this feature as enabled on the pool, but the
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|
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
|
|
The state of supported features is exposed through pool properties of the form
|
|
\fIfeature@short_name\fR.
|
|
.SS "Read\-only compatibility"
|
|
.sp
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|
.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 \fBzpool\fR(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_guid\fR will indicate why the import was allowed
|
|
despite the unsupported feature. Possible values for this property are:
|
|
|
|
.sp
|
|
.ne 2
|
|
.na
|
|
\fB\fBinactive\fR\fR
|
|
.ad
|
|
.RS 12n
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|
The feature is in the \fBenabled\fR 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
|
|
\fB\fBreadonly\fR\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.
|
|
.SH FEATURES
|
|
.sp
|
|
.LP
|
|
The following features are supported on this system:
|
|
.sp
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|
.ne 2
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|
.na
|
|
\fB\fBasync_destroy\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID com.delphix:async_destroy
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|
READ\-ONLY COMPATIBLE yes
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|
DEPENDENCIES none
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|
.TE
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|
|
|
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
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is not fully removed until all space has been reclaimed. If the destroy
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|
operation is interrupted by a reboot or power outage the next attempt to open
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|
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
|
|
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
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|
.na
|
|
\fB\fBempty_bpobj\fR\fR
|
|
.ad
|
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.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID com.delphix:empty_bpobj
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|
READ\-ONLY COMPATIBLE yes
|
|
DEPENDENCIES none
|
|
.TE
|
|
|
|
This feature increases the performance of creating and using a large
|
|
number of snapshots of a single filesystem or volume, and also reduces
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|
the disk space required.
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|
|
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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,
|
|
or snapshots which were created after enabling this feature.
|
|
.RE
|
|
|
|
.sp
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.ne 2
|
|
.na
|
|
\fB\fBfilesystem_limits\fR\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
|
|
\fB\fBlz4_compress\fR\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
|
|
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 \fBzfs\fR(8) command. Please note that doing so will
|
|
immediately activate the \fBlz4_compress\fR feature on the underlying
|
|
pool using the \fBzfs\fR(1M) 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. Booting
|
|
off of \fBlz4\fR-compressed root pools is supported.
|
|
|
|
This feature becomes \fBactive\fR as soon as it is enabled and will
|
|
never return to being \fBenabled\fB.
|
|
.RE
|
|
|
|
.sp
|
|
.ne 2
|
|
.na
|
|
\fB\fBspacemap_histogram\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID com.delphix:spacemap_histogram
|
|
READ\-ONLY COMPATIBLE yes
|
|
DEPENDENCIES none
|
|
.TE
|
|
|
|
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
|
|
\fB\fBmulti_vdev_crash_dump\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID com.joyent:multi_vdev_crash_dump
|
|
READ\-ONLY COMPATIBLE no
|
|
DEPENDENCIES none
|
|
.TE
|
|
|
|
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 Linux this feature is registered for compatibility but not used.
|
|
New pools created under 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 Linux. Existing pools
|
|
where this feature is \fB\fBactive\fR can be imported.
|
|
.RE
|
|
|
|
.sp
|
|
.ne 2
|
|
.na
|
|
\fB\fBextensible_dataset\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID com.delphix:extensible_dataset
|
|
READ\-ONLY COMPATIBLE no
|
|
DEPENDENCIES none
|
|
.TE
|
|
|
|
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
|
|
\fB\fBbookmarks\fR\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.
|
|
All bookmarks in the pool can be listed by running
|
|
\fBzfs list -t bookmark -r \fIpoolname\fR\fR.
|
|
|
|
.RE
|
|
|
|
.sp
|
|
.ne 2
|
|
.na
|
|
\fB\fBenabled_txg\fR\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
|
|
\fB\fBhole_birth\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID com.delphix:hole_birth
|
|
READ\-ONLY COMPATIBLE no
|
|
DEPENDENCIES enabled_txg
|
|
.TE
|
|
|
|
This feature improves performance of incremental sends ("zfs send -i")
|
|
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
|
|
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
|
|
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
|
|
\fB\fBembedded_data\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID com.delphix:embedded_data
|
|
READ\-ONLY COMPATIBLE no
|
|
DEPENDENCIES none
|
|
.TE
|
|
|
|
This feature improves the performance and compression ratio of
|
|
highly-compressible blocks. Blocks whose contents can compress to 112 bytes
|
|
or smaller can take advantage of this feature.
|
|
|
|
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
|
|
\fB\fBdevice_removal\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID com.delphix:device_removal
|
|
READ\-ONLY COMPATIBLE no
|
|
DEPENDENCIES none
|
|
.TE
|
|
|
|
This feature enables the "zpool remove" subcommand to remove top-level
|
|
vdevs, evacuating them to reduce the total size of the pool.
|
|
|
|
This feature becomes \fBactive\fR when the "zpool remove" command is used
|
|
on a top-level vdev, and will never return to being \fBenabled\fR.
|
|
|
|
.RE
|
|
.sp
|
|
.ne 2
|
|
.na
|
|
\fB\fBobsolete_counts\fR\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. See also the \fBzfs remap\fR
|
|
subcommand in \fBzfs\fR(1M).
|
|
|
|
This feature becomes \fBactive\fR when the "zpool remove" command is
|
|
used on a top-level vdev, and will never return to being \fBenabled\fR.
|
|
|
|
.RE
|
|
.sp
|
|
.ne 2
|
|
.na
|
|
\fB\fBlarge_blocks\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID org.open-zfs:large_block
|
|
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
|
|
\fB\fBlarge_dnode\fR\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
|
|
|
|
\fB\fBsha512\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID org.illumos:sha512
|
|
READ\-ONLY COMPATIBLE no
|
|
DEPENDENCIES extensible_dataset
|
|
.TE
|
|
|
|
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 the
|
|
\fBzfs set checksum=sha512\fR(1M) command. 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.
|
|
|
|
Booting off of pools utilizing SHA-512/256 is supported (provided that
|
|
the updated GRUB stage2 module is installed).
|
|
|
|
.RE
|
|
|
|
.sp
|
|
.ne 2
|
|
.na
|
|
\fB\fBskein\fR\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
|
|
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 the
|
|
\fBzfs set checksum=skein\fR(1M) command. 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.
|
|
|
|
Booting off of pools using \fBskein\fR is \fBNOT\fR supported
|
|
-- any attempt to enable \fBskein\fR on a root pool will fail with an
|
|
error.
|
|
|
|
.RE
|
|
|
|
.sp
|
|
.ne 2
|
|
.na
|
|
\fB\fBedonr\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID org.illumos:edonr
|
|
READ\-ONLY COMPATIBLE no
|
|
DEPENDENCIES extensible_dataset
|
|
.TE
|
|
|
|
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 can not be used with dedup
|
|
(without verification).
|
|
|
|
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.
|
|
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(1M) command. 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.
|
|
|
|
Booting off of pools using \fBedonr\fR is \fBNOT\fR supported
|
|
-- any attempt to enable \fBedonr\fR on a root pool will fail with an
|
|
error.
|
|
|
|
.RE
|
|
|
|
.sp
|
|
.ne 2
|
|
.na
|
|
\fB\fBuserobj_accounting\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID org.zfsonlinux:userobj_accounting
|
|
READ\-ONLY COMPATIBLE yes
|
|
DEPENDENCIES extensible_dataset
|
|
.TE
|
|
|
|
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
|
|
\fB\fBencryption\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID com.datto:encryption
|
|
READ\-ONLY COMPATIBLE no
|
|
DEPENDENCIES extensible_dataset
|
|
.TE
|
|
|
|
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
|
|
\fB\fBproject_quota\fR\fR
|
|
.ad
|
|
.RS 4n
|
|
.TS
|
|
l l .
|
|
GUID org.zfsonlinux:project_quota
|
|
READ\-ONLY COMPATIBLE yes
|
|
DEPENDENCIES extensible_dataset
|
|
.TE
|
|
|
|
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
|
|
|
|
.SH "SEE ALSO"
|
|
\fBzpool\fR(8)
|