xref: /illumos-gate/usr/src/man/man8/zpool.8 (revision c55633c3)

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.Dd March 30, 2022
.Dt ZPOOL 8
.Os
.Sh NAME
.Nm zpool
.Nd configure ZFS storage pools
.Sh SYNOPSIS
.Nm
.Fl \&?
.Nm
.Cm add
.Op Fl fgLnP
.Oo Fl o Ar property Ns = Ns Ar value Oc
.Ar pool vdev Ns ...
.Nm
.Cm attach
.Op Fl f
.Oo Fl o Ar property Ns = Ns Ar value Oc
.Ar pool device new_device
.Nm
.Cm checkpoint
.Op Fl d, -discard
.Ar pool
.Nm
.Cm clear
.Ar pool
.Op Ar device
.Nm
.Cm create
.Op Fl dfn
.Op Fl B
.Op Fl m Ar mountpoint
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Oo Fl o Cm feature@ Ns Ar feature Ns = Ns Ar value Oc Ns ...
.Oo Fl O Ar file-system-property Ns = Ns Ar value Oc Ns ...
.Op Fl R Ar root
.Op Fl t Ar tempname
.Ar pool vdev Ns ...
.Nm
.Cm destroy
.Op Fl f
.Ar pool
.Nm
.Cm detach
.Ar pool device
.Nm
.Cm export
.Op Fl f
.Ar pool Ns ...
.Nm
.Cm get
.Op Fl Hp
.Op Fl o Ar field Ns Oo , Ns Ar field Oc Ns ...
.Sy all Ns | Ns Ar property Ns Oo , Ns Ar property Oc Ns ...
.Ar pool Ns ...
.Nm
.Cm history
.Op Fl il
.Oo Ar pool Oc Ns ...
.Nm
.Cm import
.Op Fl D
.Op Fl d Ar dir
.Nm
.Cm import
.Fl a
.Op Fl DflmN
.Op Fl F Op Fl n
.Op Fl c Ar cachefile Ns | Ns Fl d Ar dir
.Op Fl o Ar mntopts
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Op Fl R Ar root
.Nm
.Cm import
.Op Fl Dfmt
.Op Fl F Op Fl n
.Op Fl -rewind-to-checkpoint
.Op Fl c Ar cachefile Ns | Ns Fl d Ar dir
.Op Fl o Ar mntopts
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Op Fl R Ar root
.Ar pool Ns | Ns Ar id
.Op Ar newpool
.Nm
.Cm initialize
.Op Fl c | Fl s
.Ar pool
.Op Ar device Ns ...
.Nm
.Cm iostat
.Op Oo Fl lq Oc | Ns Fl rw
.Op Fl T Sy u Ns | Ns Sy d
.Op Fl ghHLnpPvy
.Oo Oo Ar pool Ns ... Oc Ns | Ns Oo Ar pool vdev Ns ... Oc Ns | Ns Oo Ar vdev Ns ... Oc Oc
.Op Ar interval Op Ar count
.Nm
.Cm labelclear
.Op Fl f
.Ar device
.Nm
.Cm list
.Op Fl HgLpPv
.Op Fl o Ar property Ns Oo , Ns Ar property Oc Ns ...
.Op Fl T Sy u Ns | Ns Sy d
.Oo Ar pool Oc Ns ...
.Op Ar interval Op Ar count
.Nm
.Cm offline
.Op Fl t
.Ar pool Ar device Ns ...
.Nm
.Cm online
.Op Fl e
.Ar pool Ar device Ns ...
.Nm
.Cm reguid
.Ar pool
.Nm
.Cm reopen
.Ar pool
.Nm
.Cm remove
.Op Fl np
.Ar pool Ar device Ns ...
.Nm
.Cm remove
.Fl s
.Ar pool
.Nm
.Cm replace
.Op Fl f
.Ar pool Ar device Op Ar new_device
.Nm
.Cm resilver
.Ar pool Ns ...
.Nm
.Cm scrub
.Op Fl s | Fl p
.Ar pool Ns ...
.Nm
.Cm trim
.Op Fl d
.Op Fl r Ar rate
.Op Fl c | Fl s
.Ar pool
.Op Ar device Ns ...
.Nm
.Cm set
.Ar property Ns = Ns Ar value
.Ar pool
.Nm
.Cm split
.Op Fl gLlnP
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Op Fl R Ar root
.Ar pool newpool
.Nm
.Cm status
.Op Fl DigLpPstvx
.Op Fl T Sy u Ns | Ns Sy d
.Oo Ar pool Oc Ns ...
.Op Ar interval Op Ar count
.Nm
.Cm sync
.Oo Ar pool Oc Ns ...
.Nm
.Cm upgrade
.Nm
.Cm upgrade
.Fl v
.Nm
.Cm upgrade
.Op Fl V Ar version
.Fl a Ns | Ns Ar pool Ns ...
.Sh DESCRIPTION
The
.Nm
command configures ZFS storage pools.
A storage pool is a collection of devices that provides physical storage and
data replication for ZFS datasets.
All datasets within a storage pool share the same space.
See
.Xr zfs 8
for information on managing datasets.
.Ss Virtual Devices (vdevs)
A "virtual device" describes a single device or a collection of devices
organized according to certain performance and fault characteristics.
The following virtual devices are supported:
.Bl -tag -width Ds
.It Sy disk
A block device, typically located under
.Pa /dev/dsk .
ZFS can use individual slices or partitions, though the recommended mode of
operation is to use whole disks.
A disk can be specified by a full path, or it can be a shorthand name
.Po the relative portion of the path under
.Pa /dev/dsk
.Pc .
A whole disk can be specified by omitting the slice or partition designation.
For example,
.Pa c0t0d0
is equivalent to
.Pa /dev/dsk/c0t0d0s2 .
When given a whole disk, ZFS automatically labels the disk, if necessary.
.It Sy file
A regular file.
The use of files as a backing store is strongly discouraged.
It is designed primarily for experimental purposes, as the fault tolerance of a
file is only as good as the file system of which it is a part.
A file must be specified by a full path.
.It Sy mirror
A mirror of two or more devices.
Data is replicated in an identical fashion across all components of a mirror.
A mirror with N disks of size X can hold X bytes and can withstand (N-1) devices
failing before data integrity is compromised.
.It Sy raidz , raidz1 , raidz2 , raidz3
A variation on RAID-5 that allows for better distribution of parity and
eliminates the RAID-5
.Qq write hole
.Pq in which data and parity become inconsistent after a power loss .
Data and parity is striped across all disks within a raidz group.
.Pp
A raidz group can have single-, double-, or triple-parity, meaning that the
raidz group can sustain one, two, or three failures, respectively, without
losing any data.
The
.Sy raidz1
vdev type specifies a single-parity raidz group; the
.Sy raidz2
vdev type specifies a double-parity raidz group; and the
.Sy raidz3
vdev type specifies a triple-parity raidz group.
The
.Sy raidz
vdev type is an alias for
.Sy raidz1 .
.Pp
A raidz group with N disks of size X with P parity disks can hold approximately
(N-P)*X bytes and can withstand P device(s) failing before data integrity is
compromised.
The minimum number of devices in a raidz group is one more than the number of
parity disks.
The recommended number is between 3 and 9 to help increase performance.
.It Sy spare
A special pseudo-vdev which keeps track of available hot spares for a pool.
For more information, see the
.Sx Hot Spares
section.
.It Sy log
A separate intent log device.
If more than one log device is specified, then writes are load-balanced between
devices.
Log devices can be mirrored.
However, raidz vdev types are not supported for the intent log.
For more information, see the
.Sx Intent Log
section.
.It Sy dedup
A device dedicated solely for allocating dedup data.
The redundancy of this device should match the redundancy of the other normal
devices in the pool.
If more than one dedup device is specified, then allocations are load-balanced
between devices.
.It Sy special
A device dedicated solely for allocating various kinds of internal metadata,
and optionally small file data.
The redundancy of this device should match the redundancy of the other normal
devices in the pool.
If more than one special device is specified, then allocations are
load-balanced between devices.
.Pp
For more information on special allocations, see the
.Sx Special Allocation Class
section.
.It Sy cache
A device used to cache storage pool data.
A cache device cannot be configured as a mirror or raidz group.
For more information, see the
.Sx Cache Devices
section.
.El
.Pp
Virtual devices cannot be nested, so a mirror or raidz virtual device can only
contain files or disks.
Mirrors of mirrors
.Pq or other combinations
are not allowed.
.Pp
A pool can have any number of virtual devices at the top of the configuration
.Po known as
.Qq root vdevs
.Pc .
Data is dynamically distributed across all top-level devices to balance data
among devices.
As new virtual devices are added, ZFS automatically places data on the newly
available devices.
.Pp
Virtual devices are specified one at a time on the command line, separated by
whitespace.
The keywords
.Sy mirror
and
.Sy raidz
are used to distinguish where a group ends and another begins.
For example, the following creates two root vdevs, each a mirror of two disks:
.Bd -literal
# zpool create mypool mirror c0t0d0 c0t1d0 mirror c1t0d0 c1t1d0
.Ed
.Ss Device Failure and Recovery
ZFS supports a rich set of mechanisms for handling device failure and data
corruption.
All metadata and data is checksummed, and ZFS automatically repairs bad data
from a good copy when corruption is detected.
.Pp
In order to take advantage of these features, a pool must make use of some form
of redundancy, using either mirrored or raidz groups.
While ZFS supports running in a non-redundant configuration, where each root
vdev is simply a disk or file, this is strongly discouraged.
A single case of bit corruption can render some or all of your data unavailable.
.Pp
A pool's health status is described by one of three states: online, degraded,
or faulted.
An online pool has all devices operating normally.
A degraded pool is one in which one or more devices have failed, but the data is
still available due to a redundant configuration.
A faulted pool has corrupted metadata, or one or more faulted devices, and
insufficient replicas to continue functioning.
.Pp
The health of the top-level vdev, such as mirror or raidz device, is
potentially impacted by the state of its associated vdevs, or component
devices.
A top-level vdev or component device is in one of the following states:
.Bl -tag -width "DEGRADED"
.It Sy DEGRADED
One or more top-level vdevs is in the degraded state because one or more
component devices are offline.
Sufficient replicas exist to continue functioning.
.Pp
One or more component devices is in the degraded or faulted state, but
sufficient replicas exist to continue functioning.
The underlying conditions are as follows:
.Bl -bullet
.It
The number of checksum errors exceeds acceptable levels and the device is
degraded as an indication that something may be wrong.
ZFS continues to use the device as necessary.
.It
The number of I/O errors exceeds acceptable levels.
The device could not be marked as faulted because there are insufficient
replicas to continue functioning.
.El
.It Sy FAULTED
One or more top-level vdevs is in the faulted state because one or more
component devices are offline.
Insufficient replicas exist to continue functioning.
.Pp
One or more component devices is in the faulted state, and insufficient
replicas exist to continue functioning.
The underlying conditions are as follows:
.Bl -bullet
.It
The device could be opened, but the contents did not match expected values.
.It
The number of I/O errors exceeds acceptable levels and the device is faulted to
prevent further use of the device.
.El
.It Sy OFFLINE
The device was explicitly taken offline by the
.Nm zpool Cm offline
command.
.It Sy ONLINE
The device is online and functioning.
.It Sy REMOVED
The device was physically removed while the system was running.
Device removal detection is hardware-dependent and may not be supported on all
platforms.
.It Sy UNAVAIL
The device could not be opened.
If a pool is imported when a device was unavailable, then the device will be
identified by a unique identifier instead of its path since the path was never
correct in the first place.
.El
.Pp
If a device is removed and later re-attached to the system, ZFS attempts
to put the device online automatically.
Device attach detection is hardware-dependent and might not be supported on all
platforms.
.Ss Hot Spares
ZFS allows devices to be associated with pools as
.Qq hot spares .
These devices are not actively used in the pool, but when an active device
fails, it is automatically replaced by a hot spare.
To create a pool with hot spares, specify a
.Sy spare
vdev with any number of devices.
For example,
.Bd -literal
# zpool create pool mirror c0d0 c1d0 spare c2d0 c3d0
.Ed
.Pp
Spares can be shared across multiple pools, and can be added with the
.Nm zpool Cm add
command and removed with the
.Nm zpool Cm remove
command.
Once a spare replacement is initiated, a new
.Sy spare
vdev is created within the configuration that will remain there until the
original device is replaced.
At this point, the hot spare becomes available again if another device fails.
.Pp
If a pool has a shared spare that is currently being used, the pool can not be
exported since other pools may use this shared spare, which may lead to
potential data corruption.
.Pp
Shared spares add some risk.
If the pools are imported on different hosts, and both pools suffer a device
failure at the same time, both could attempt to use the spare at the same time.
This may not be detected, resulting in data corruption.
.Pp
An in-progress spare replacement can be cancelled by detaching the hot spare.
If the original faulted device is detached, then the hot spare assumes its
place in the configuration, and is removed from the spare list of all active
pools.
.Pp
Spares cannot replace log devices.
.Ss Intent Log
The ZFS Intent Log (ZIL) satisfies POSIX requirements for synchronous
transactions.
For instance, databases often require their transactions to be on stable storage
devices when returning from a system call.
NFS and other applications can also use
.Xr fsync 3C
to ensure data stability.
By default, the intent log is allocated from blocks within the main pool.
However, it might be possible to get better performance using separate intent
log devices such as NVRAM or a dedicated disk.
For example:
.Bd -literal
# zpool create pool c0d0 c1d0 log c2d0
.Ed
.Pp
Multiple log devices can also be specified, and they can be mirrored.
See the
.Sx EXAMPLES
section for an example of mirroring multiple log devices.
.Pp
Log devices can be added, replaced, attached, detached, and imported and
exported as part of the larger pool.
Mirrored devices can be removed by specifying the top-level mirror vdev.
.Ss Cache Devices
Devices can be added to a storage pool as
.Qq cache devices .
These devices provide an additional layer of caching between main memory and
disk.
For read-heavy workloads, where the working set size is much larger than what
can be cached in main memory, using cache devices allow much more of this
working set to be served from low latency media.
Using cache devices provides the greatest performance improvement for random
read-workloads of mostly static content.
.Pp
To create a pool with cache devices, specify a
.Sy cache
vdev with any number of devices.
For example:
.Bd -literal
# zpool create pool c0d0 c1d0 cache c2d0 c3d0
.Ed
.Pp
Cache devices cannot be mirrored or part of a raidz configuration.
If a read error is encountered on a cache device, that read I/O is reissued to
the original storage pool device, which might be part of a mirrored or raidz
configuration.
.Pp
The content of the cache devices is considered volatile, as is the case with
other system caches.
.Ss Pool checkpoint
Before starting critical procedures that include destructive actions
.Pq e.g. zfs Cm destroy ,
an administrator can checkpoint the pool's state and in the case of a
mistake or failure, rewind the entire pool back to the checkpoint.
The checkpoint is automatically discarded upon rewinding.
Otherwise, the checkpoint can be discarded when the procedure has completed
successfully.
.Pp
A pool checkpoint can be thought of as a pool-wide snapshot and should be used
with care as it contains every part of the pool's state, from properties to vdev
configuration.
Thus, while a pool has a checkpoint certain operations are not allowed.
Specifically, vdev removal/attach/detach, mirror splitting, and
changing the pool's guid.
Adding a new vdev is supported but in the case of a rewind it will have to be
added again.
Finally, users of this feature should keep in mind that scrubs in a pool that
has a checkpoint do not repair checkpointed data.
.Pp
To create a checkpoint for a pool:
.Bd -literal
# zpool checkpoint pool
.Ed
.Pp
To later rewind to its checkpointed state (which also discards the checkpoint),
you need to first export it and then rewind it during import:
.Bd -literal
# zpool export pool
# zpool import --rewind-to-checkpoint pool
.Ed
.Pp
To discard the checkpoint from a pool without rewinding:
.Bd -literal
# zpool checkpoint -d pool
.Ed
.Pp
Dataset reservations (controlled by the
.Nm reservation
or
.Nm refreservation
zfs properties) may be unenforceable while a checkpoint exists, because the
checkpoint is allowed to consume the dataset's reservation.
Finally, data that is part of the checkpoint but has been freed in the
current state of the pool won't be scanned during a scrub.
.Ss Special Allocation Class
The allocations in the special class are dedicated to specific block types.
By default this includes all metadata, the indirect blocks of user data, and
any dedup data.
The class can also be provisioned to accept a limited percentage of small file
data blocks.
.Pp
A pool must always have at least one general (non-specified) vdev before
other devices can be assigned to the special class.
If the special class becomes full, then allocations intended for it will spill
back into the normal class.
.Pp
Dedup data can be excluded from the special class by setting the
.Sy zfs_ddt_data_is_special
zfs kernel variable to false (0).
.Pp
Inclusion of small file blocks in the special class is opt-in.
Each dataset can control the size of small file blocks allowed in the special
class by setting the
.Sy special_small_blocks
dataset property.
It defaults to zero so you must opt-in by setting it to a non-zero value.
See
.Xr zfs 8
for more info on setting this property.
.Ss Properties
Each pool has several properties associated with it.
Some properties are read-only statistics while others are configurable and
change the behavior of the pool.
.Pp
The following are read-only properties:
.Bl -tag -width Ds
.It Cm allocated
Amount of storage space used within the pool.
.It Sy bootsize
The size of the system boot partition.
This property can only be set at pool creation time and is read-only once pool
is created.
Setting this property implies using the
.Fl B
option.
.It Sy capacity
Percentage of pool space used.
This property can also be referred to by its shortened column name,
.Sy cap .
.It Sy expandsize
Amount of uninitialized space within the pool or device that can be used to
increase the total capacity of the pool.
Uninitialized space consists of any space on an EFI labeled vdev which has not
been brought online
.Po e.g, using
.Nm zpool Cm online Fl e
.Pc .
This space occurs when a LUN is dynamically expanded.
.It Sy fragmentation
The amount of fragmentation in the pool.
.It Sy free
The amount of free space available in the pool.
.It Sy freeing
After a file system or snapshot is destroyed, the space it was using is
returned to the pool asynchronously.
.Sy freeing
is the amount of space remaining to be reclaimed.
Over time
.Sy freeing
will decrease while
.Sy free
increases.
.It Sy health
The current health of the pool.
Health can be one of
.Sy ONLINE , DEGRADED , FAULTED , OFFLINE, REMOVED , UNAVAIL .
.It Sy guid
A unique identifier for the pool.
.It Sy size
Total size of the storage pool.
.It Sy unsupported@ Ns Em feature_guid
Information about unsupported features that are enabled on the pool.
See
.Xr zpool-features 7
for details.
.El
.Pp
The space usage properties report actual physical space available to the
storage pool.
The physical space can be different from the total amount of space that any
contained datasets can actually use.
The amount of space used in a raidz configuration depends on the characteristics
of the data being written.
In addition, ZFS reserves some space for internal accounting that the
.Xr zfs 8
command takes into account, but the
.Nm
command does not.
For non-full pools of a reasonable size, these effects should be invisible.
For small pools, or pools that are close to being completely full, these
discrepancies may become more noticeable.
.Pp
The following property can be set at creation time and import time:
.Bl -tag -width Ds
.It Sy altroot
Alternate root directory.
If set, this directory is prepended to any mount points within the pool.
This can be used when examining an unknown pool where the mount points cannot be
trusted, or in an alternate boot environment, where the typical paths are not
valid.
.Sy altroot
is not a persistent property.
It is valid only while the system is up.
Setting
.Sy altroot
defaults to using
.Sy cachefile Ns = Ns Sy none ,
though this may be overridden using an explicit setting.
.El
.Pp
The following property can be set only at import time:
.Bl -tag -width Ds
.It Sy readonly Ns = Ns Sy on Ns | Ns Sy off
If set to
.Sy on ,
the pool will be imported in read-only mode.
This property can also be referred to by its shortened column name,
.Sy rdonly .
.El
.Pp
The following properties can be set at creation time and import time, and later
changed with the
.Nm zpool Cm set
command:
.Bl -tag -width Ds
.It Sy ashift Ns = Ns Sy ashift
Pool sector size exponent, to the power of
.Sy 2
(internally referred to as
.Sy ashift
). Values from 9 to 16, inclusive, are valid; also, the
value 0 (the default) means to auto-detect using the kernel's block
layer and a ZFS internal exception list.
I/O operations will be aligned to the specified size boundaries.
Additionally, the minimum (disk) write size will be set to the specified size,
so this represents a space vs performance trade-off.
For optimal performance, the pool sector size should be greater than or equal to
the sector size of the underlying disks.
The typical case for setting this property is when performance is important and
the underlying disks use 4KiB sectors but report 512B sectors to the OS (for
compatibility reasons); in that case, set
.Sy ashift=12
(which is 1<<12 = 4096). When set, this property is
used as the default hint value in subsequent vdev operations (add,
attach and replace).
Changing this value will not modify any existing
vdev, not even on disk replacement; however it can be used, for
instance, to replace a dying 512B sectors disk with a newer 4KiB
sectors device: this will probably result in bad performance but at the
same time could prevent loss of data.
.It Sy autoexpand Ns = Ns Sy on Ns | Ns Sy off
Controls automatic pool expansion when the underlying LUN is grown.
If set to
.Sy on ,
the pool will be resized according to the size of the expanded device.
If the device is part of a mirror or raidz then all devices within that
mirror/raidz group must be expanded before the new space is made available to
the pool.
The default behavior is
.Sy off .
This property can also be referred to by its shortened column name,
.Sy expand .
.It Sy autoreplace Ns = Ns Sy on Ns | Ns Sy off
Controls automatic device replacement.
If set to
.Sy off ,
device replacement must be initiated by the administrator by using the
.Nm zpool Cm replace
command.
If set to
.Sy on ,
any new device, found in the same physical location as a device that previously
belonged to the pool, is automatically formatted and replaced.
The default behavior is
.Sy off .
This property can also be referred to by its shortened column name,
.Sy replace .
.It Sy bootfs Ns = Ns Ar pool Ns / Ns Ar dataset
Identifies the default bootable dataset for the root pool.
This property is expected to be set mainly by the installation and upgrade
programs.
.It Sy cachefile Ns = Ns Ar path Ns | Ns Sy none
Controls the location of where the pool configuration is cached.
Discovering all pools on system startup requires a cached copy of the
configuration data that is stored on the root file system.
All pools in this cache are automatically imported when the system boots.
Some environments, such as install and clustering, need to cache this
information in a different location so that pools are not automatically
imported.
Setting this property caches the pool configuration in a different location that
can later be imported with
.Nm zpool Cm import Fl c .
Setting it to the special value
.Sy none
creates a temporary pool that is never cached, and the special value
.Qq
.Pq empty string
uses the default location.
.Pp
Multiple pools can share the same cache file.
Because the kernel destroys and recreates this file when pools are added and
removed, care should be taken when attempting to access this file.
When the last pool using a
.Sy cachefile
is exported or destroyed, the file is removed.
.It Sy comment Ns = Ns Ar text
A text string consisting of printable ASCII characters that will be stored
such that it is available even if the pool becomes faulted.
An administrator can provide additional information about a pool using this
property.
.It Sy dedupditto Ns = Ns Ar number
Threshold for the number of block ditto copies.
If the reference count for a deduplicated block increases above this number, a
new ditto copy of this block is automatically stored.
The default setting is
.Sy 0
which causes no ditto copies to be created for deduplicated blocks.
The minimum legal nonzero setting is
.Sy 100 .
.It Sy delegation Ns = Ns Sy on Ns | Ns Sy off
Controls whether a non-privileged user is granted access based on the dataset
permissions defined on the dataset.
See
.Xr zfs 8
for more information on ZFS delegated administration.
.It Sy failmode Ns = Ns Sy wait Ns | Ns Sy continue Ns | Ns Sy panic
Controls the system behavior in the event of catastrophic pool failure.
This condition is typically a result of a loss of connectivity to the underlying
storage device(s) or a failure of all devices within the pool.
The behavior of such an event is determined as follows:
.Bl -tag -width "continue"
.It Sy wait
Blocks all I/O access until the device connectivity is recovered and the errors
are cleared.
This is the default behavior.
.It Sy continue
Returns
.Er EIO
to any new write I/O requests but allows reads to any of the remaining healthy
devices.
Any write requests that have yet to be committed to disk would be blocked.
.It Sy panic
Prints out a message to the console and generates a system crash dump.
.El
.It Sy autotrim Ns = Ns Sy on Ns | Ns Sy off
When set to
.Sy on
space which has been recently freed, and is no longer allocated by the pool,
will be periodically trimmed.
This allows block device vdevs which support BLKDISCARD, such as SSDs, or
file vdevs on which the underlying file system supports hole-punching, to
reclaim unused blocks.
The default setting for this property is
.Sy off .
.Pp
Automatic TRIM does not immediately reclaim blocks after a free.
Instead, it will optimistically delay allowing smaller ranges to be
aggregated in to a few larger ones.
These can then be issued more efficiently to the storage.
.Pp
Be aware that automatic trimming of recently freed data blocks can put
significant stress on the underlying storage devices.
This will vary depending of how well the specific device handles these commands.
For lower end devices it is often possible to achieve most of the benefits
of automatic trimming by running an on-demand (manual) TRIM periodically
using the
.Nm zpool Cm trim
command.
.It Sy feature@ Ns Ar feature_name Ns = Ns Sy enabled
The value of this property is the current state of
.Ar feature_name .
The only valid value when setting this property is
.Sy enabled
which moves
.Ar feature_name
to the enabled state.
See
.Xr zpool-features 7
for details on feature states.
.It Sy listsnapshots Ns = Ns Sy on Ns | Ns Sy off
Controls whether information about snapshots associated with this pool is
output when
.Nm zfs Cm list
is run without the
.Fl t
option.
The default value is
.Sy off .
This property can also be referred to by its shortened name,
.Sy listsnaps .
.It Sy multihost Ns = Ns Sy on Ns | Ns Sy off
Controls whether a pool activity check should be performed during
.Nm zpool Cm import .
When a pool is determined to be active it cannot be imported, even with the
.Fl f
option.
This property is intended to be used in failover configurations
where multiple hosts have access to a pool on shared storage.
.sp
Multihost provides protection on import only.
It does not protect against an
individual device being used in multiple pools, regardless of the type of vdev.
See the discussion under
.Sy zpool create.
.sp
When this property is on, periodic writes to storage occur to show the pool is
in use.
See
.Sy zfs_multihost_interval
in the
.Xr zfs-module-parameters 7
man page.
In order to enable this property each host must set a unique hostid.
The default value is
.Sy off .
.It Sy version Ns = Ns Ar version
The current on-disk version of the pool.
This can be increased, but never decreased.
The preferred method of updating pools is with the
.Nm zpool Cm upgrade
command, though this property can be used when a specific version is needed for
backwards compatibility.
Once feature flags are enabled on a pool this property will no longer have a
value.
.El
.Ss Subcommands
All subcommands that modify state are logged persistently to the pool in their
original form.
.Pp
The
.Nm
command provides subcommands to create and destroy storage pools, add capacity
to storage pools, and provide information about the storage pools.
The following subcommands are supported:
.Bl -tag -width Ds
.It Xo
.Nm
.Fl \&?
.Xc
Displays a help message.
.It Xo
.Nm
.Cm add
.Op Fl fgLnP
.Oo Fl o Ar property Ns = Ns Ar value Oc
.Ar pool vdev Ns ...
.Xc
Adds the specified virtual devices to the given pool.
The
.Ar vdev
specification is described in the
.Sx Virtual Devices
section.
The behavior of the
.Fl f
option, and the device checks performed are described in the
.Nm zpool Cm create
subcommand.
.Bl -tag -width Ds
.It Fl f
Forces use of
.Ar vdev Ns s ,
even if they appear in use or specify a conflicting replication level.
Not all devices can be overridden in this manner.
.It Fl g
Display
.Ar vdev ,
GUIDs instead of the normal device names.
These GUIDs can be used in place of
device names for the zpool detach/offline/remove/replace commands.
.It Fl L
Display real paths for
.Ar vdev Ns s
resolving all symbolic links.
This can be used to look up the current block
device name regardless of the /dev/disk/ path used to open it.
.It Fl n
Displays the configuration that would be used without actually adding the
.Ar vdev Ns s .
The actual pool creation can still fail due to insufficient privileges or
device sharing.
.It Fl P
Display real paths for
.Ar vdev Ns s
instead of only the last component of the path.
This can be used in conjunction with the
.Fl L
flag.
.It Fl o Ar property Ns = Ns Ar value
Sets the given pool properties.
See the
.Sx Properties
section for a list of valid properties that can be set.
The only property supported at the moment is
.Sy ashift.
.El
.It Xo
.Nm
.Cm attach
.Op Fl f
.Oo Fl o Ar property Ns = Ns Ar value Oc
.Ar pool device new_device
.Xc
Attaches
.Ar new_device
to the existing
.Ar device .
The existing device cannot be part of a raidz configuration.
If
.Ar device
is not currently part of a mirrored configuration,
.Ar device
automatically transforms into a two-way mirror of
.Ar device
and
.Ar new_device .
If
.Ar device
is part of a two-way mirror, attaching
.Ar new_device
creates a three-way mirror, and so on.
In either case,
.Ar new_device
begins to resilver immediately.
.Bl -tag -width Ds
.It Fl f
Forces use of
.Ar new_device ,
even if its appears to be in use.
Not all devices can be overridden in this manner.
.It Fl o Ar property Ns = Ns Ar value
Sets the given pool properties.
See the
.Sx Properties
section for a list of valid properties that can be set.
The only property supported at the moment is
.Sy ashift.
.El
.It Xo
.Nm
.Cm checkpoint
.Op Fl d, -discard
.Ar pool
.Xc
Checkpoints the current state of
.Ar pool
, which can be later restored by
.Nm zpool Cm import --rewind-to-checkpoint .
Rewinding will also discard the checkpoint.
The existence of a checkpoint in a pool prohibits the following
.Nm zpool
commands:
.Cm remove ,
.Cm attach ,
.Cm detach ,
.Cm split ,
and
.Cm reguid .
In addition, it may break reservation boundaries if the pool lacks free
space.
The
.Nm zpool Cm status
command indicates the existence of a checkpoint or the progress of discarding a
checkpoint from a pool.
The
.Nm zpool Cm list
command reports how much space the checkpoint takes from the pool.
.Bl -tag -width Ds
.It Fl d, -discard
Discards an existing checkpoint from
.Ar pool
without rewinding.
.El
.It Xo
.Nm
.Cm clear
.Ar pool
.Op Ar device
.Xc
Clears device errors in a pool.
If no arguments are specified, all device errors within the pool are cleared.
If one or more devices is specified, only those errors associated with the
specified device or devices are cleared.
If multihost is enabled, and the pool has been suspended, this will not
resume I/O.
While the pool was suspended, it may have been imported on
another host, and resuming I/O could result in pool damage.
.It Xo
.Nm
.Cm create
.Op Fl dfn
.Op Fl B
.Op Fl m Ar mountpoint
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Oo Fl o Cm feature@ Ns Ar feature Ns = Ns Ar value Oc Ns ...
.Oo Fl O Ar file-system-property Ns = Ns Ar value Oc Ns ...
.Op Fl R Ar root
.Op Fl t Ar tempname
.Ar pool vdev Ns ...
.Xc
Creates a new storage pool containing the virtual devices specified on the
command line.
The pool name must begin with a letter, and can only contain
alphanumeric characters as well as underscore
.Pq Qq Sy _ ,
dash
.Pq Qq Sy - ,
and period
.Pq Qq Sy \&. .
The pool names
.Sy mirror ,
.Sy raidz ,
.Sy spare
and
.Sy log
are reserved, as are names beginning with the pattern
.Sy c[0-9] .
The
.Ar vdev
specification is described in the
.Sx Virtual Devices
section.
.Pp
The command attempts to verify that each device specified is accessible and not
currently in use by another subsystem.
However this check is not robust enough
to detect simultaneous attempts to use a new device in different pools, even if
.Sy multihost
is
.Sy enabled.
The
administrator must ensure that simultaneous invocations of any combination of
.Sy zpool replace ,
.Sy zpool create ,
.Sy zpool add ,
or
.Sy zpool labelclear ,
do not refer to the same device.
Using the same device in two pools will
result in pool corruption.
.sp
There are some uses, such as being currently mounted, or specified as the
dedicated dump device, that prevents a device from ever being used by ZFS.
Other uses, such as having a preexisting UFS file system, can be overridden with
the
.Fl f
option.
.Pp
The command also checks that the replication strategy for the pool is
consistent.
An attempt to combine redundant and non-redundant storage in a single pool, or
to mix disks and files, results in an error unless
.Fl f
is specified.
The use of differently sized devices within a single raidz or mirror group is
also flagged as an error unless
.Fl f
is specified.
.Pp
Unless the
.Fl R
option is specified, the default mount point is
.Pa / Ns Ar pool .
The mount point must not exist or must be empty, or else the root dataset
cannot be mounted.
This can be overridden with the
.Fl m
option.
.Pp
By default all supported features are enabled on the new pool unless the
.Fl d
option is specified.
.Bl -tag -width Ds
.It Fl B
Create whole disk pool with EFI System partition to support booting system
with UEFI firmware.
Default size is 256MB.
To create boot partition with custom size, set the
.Sy bootsize
property with the
.Fl o
option.
See the
.Sx Properties
section for details.
.It Fl d
Do not enable any features on the new pool.
Individual features can be enabled by setting their corresponding properties to
.Sy enabled
with the
.Fl o
option.
See
.Xr zpool-features 7
for details about feature properties.
.It Fl f
Forces use of
.Ar vdev Ns s ,
even if they appear in use or specify a conflicting replication level.
Not all devices can be overridden in this manner.
.It Fl m Ar mountpoint
Sets the mount point for the root dataset.
The default mount point is
.Pa /pool
or
.Pa altroot/pool
if
.Ar altroot
is specified.
The mount point must be an absolute path,
.Sy legacy ,
or
.Sy none .
For more information on dataset mount points, see
.Xr zfs 8 .
.It Fl n
Displays the configuration that would be used without actually creating the
pool.
The actual pool creation can still fail due to insufficient privileges or
device sharing.
.It Fl o Ar property Ns = Ns Ar value
Sets the given pool properties.
See the
.Sx Properties
section for a list of valid properties that can be set.
.It Fl o Cm feature@ Ns Ar feature Ns = Ns Ar value
Sets the given pool feature.
See
.Xr zpool-features 7
for a list of valid features that can be set.
.Pp
.Ar value
can either be
.Sy disabled
or
.Sy enabled .
.It Fl O Ar file-system-property Ns = Ns Ar value
Sets the given file system properties in the root file system of the pool.
See the
.Sx Properties
section of
.Xr zfs 8
for a list of valid properties that can be set.
.It Fl R Ar root
Equivalent to
.Fl o Sy cachefile Ns = Ns Sy none Fl o Sy altroot Ns = Ns Ar root
.It Fl t Ar tempname
Sets the in-core pool name to
.Pa tempname
while the on-disk name will be the name specified as the pool name
.Pa pool .
This will set the default cachefile property to
.Sy none.
This is intended to handle name space collisions when creating pools
for other systems, such as virtual machines or physical machines
whose pools live on network block devices.
.El
.It Xo
.Nm
.Cm destroy
.Op Fl f
.Ar pool
.Xc
Destroys the given pool, freeing up any devices for other use.
This command tries to unmount any active datasets before destroying the pool.
.Bl -tag -width Ds
.It Fl f
Forces any active datasets contained within the pool to be unmounted.
.El
.It Xo
.Nm
.Cm detach
.Ar pool device
.Xc
Detaches
.Ar device
from a mirror.
The operation is refused if there are no other valid replicas of the data.
.It Xo
.Nm
.Cm export
.Op Fl f
.Ar pool Ns ...
.Xc
Exports the given pools from the system.
All devices are marked as exported, but are still considered in use by other
subsystems.
The devices can be moved between systems
.Pq even those of different endianness
and imported as long as a sufficient number of devices are present.
.Pp
Before exporting the pool, all datasets within the pool are unmounted.
A pool can not be exported if it has a shared spare that is currently being
used.
.Pp
For pools to be portable, you must give the
.Nm
command whole disks, not just slices, so that ZFS can label the disks with
portable EFI labels.
Otherwise, disk drivers on platforms of different endianness will not recognize
the disks.
.Bl -tag -width Ds
.It Fl f
Forcefully unmount all datasets, using the
.Nm unmount Fl f
command.
.Pp
This command will forcefully export the pool even if it has a shared spare that
is currently being used.
This may lead to potential data corruption.
.El
.It Xo
.Nm
.Cm get
.Op Fl Hp
.Op Fl o Ar field Ns Oo , Ns Ar field Oc Ns ...
.Sy all Ns | Ns Ar property Ns Oo , Ns Ar property Oc Ns ...
.Ar pool Ns ...
.Xc
Retrieves the given list of properties
.Po
or all properties if
.Sy all
is used
.Pc
for the specified storage pool(s).
These properties are displayed with the following fields:
.Bd -literal
        name          Name of storage pool
        property      Property name
        value         Property value
        source        Property source, either 'default' or 'local'.
.Ed
.Pp
See the
.Sx Properties
section for more information on the available pool properties.
.Bl -tag -width Ds
.It Fl H
Scripted mode.
Do not display headers, and separate fields by a single tab instead of arbitrary
space.
.It Fl o Ar field
A comma-separated list of columns to display.
.Sy name Ns \&, Ns Sy property Ns \&, Ns Sy value Ns \&, Ns Sy source
is the default value.
.It Fl p
Display numbers in parsable (exact) values.
.El
.It Xo
.Nm
.Cm history
.Op Fl il
.Oo Ar pool Oc Ns ...
.Xc
Displays the command history of the specified pool(s) or all pools if no pool is
specified.
.Bl -tag -width Ds
.It Fl i
Displays internally logged ZFS events in addition to user initiated events.
.It Fl l
Displays log records in long format, which in addition to standard format
includes, the user name, the hostname, and the zone in which the operation was
performed.
.El
.It Xo
.Nm
.Cm import
.Op Fl D
.Op Fl d Ar dir
.Xc
Lists pools available to import.
If the
.Fl d
option is not specified, this command searches for devices in
.Pa /dev/dsk .
The
.Fl d
option can be specified multiple times, and all directories are searched.
If the device appears to be part of an exported pool, this command displays a
summary of the pool with the name of the pool, a numeric identifier, as well as
the vdev layout and current health of the device for each device or file.
Destroyed pools, pools that were previously destroyed with the
.Nm zpool Cm destroy
command, are not listed unless the
.Fl D
option is specified.
.Pp
The numeric identifier is unique, and can be used instead of the pool name when
multiple exported pools of the same name are available.
.Bl -tag -width Ds
.It Fl c Ar cachefile
Reads configuration from the given
.Ar cachefile
that was created with the
.Sy cachefile
pool property.
This
.Ar cachefile
is used instead of searching for devices.
.It Fl d Ar dir
Searches for devices or files in
.Ar dir .
The
.Fl d
option can be specified multiple times.
.It Fl D
Lists destroyed pools only.
.El
.It Xo
.Nm
.Cm import
.Fl a
.Op Fl DflmN
.Op Fl F Op Fl n
.Op Fl c Ar cachefile Ns | Ns Fl d Ar dir
.Op Fl o Ar mntopts
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Op Fl R Ar root
.Xc
Imports all pools found in the search directories.
Identical to the previous command, except that all pools with a sufficient
number of devices available are imported.
Destroyed pools, pools that were previously destroyed with the
.Nm zpool Cm destroy
command, will not be imported unless the
.Fl D
option is specified.
.Bl -tag -width Ds
.It Fl a
Searches for and imports all pools found.
.It Fl c Ar cachefile
Reads configuration from the given
.Ar cachefile
that was created with the
.Sy cachefile
pool property.
This
.Ar cachefile
is used instead of searching for devices.
.It Fl d Ar dir
Searches for devices or files in
.Ar dir .
The
.Fl d
option can be specified multiple times.
This option is incompatible with the
.Fl c
option.
.It Fl D
Imports destroyed pools only.
The
.Fl f
option is also required.
.It Fl f
Forces import, even if the pool appears to be potentially active.
.It Fl F
Recovery mode for a non-importable pool.
Attempt to return the pool to an importable state by discarding the last few
transactions.
Not all damaged pools can be recovered by using this option.
If successful, the data from the discarded transactions is irretrievably lost.
This option is ignored if the pool is importable or already imported.
.It Fl l
Indicates that this command will request encryption keys for all encrypted
datasets it attempts to mount as it is bringing the pool online.
Note that if any datasets have a
.Sy keylocation
of
.Sy prompt
this command will block waiting for the keys to be entered.
Without this flag encrypted datasets will be left unavailable until the keys are
loaded.
.It Fl m
Allows a pool to import when there is a missing log device.
Recent transactions can be lost because the log device will be discarded.
.It Fl n
Used with the
.Fl F
recovery option.
Determines whether a non-importable pool can be made importable again, but does
not actually perform the pool recovery.
For more details about pool recovery mode, see the
.Fl F
option, above.
.It Fl N
Import the pool without mounting any file systems.
.It Fl o Ar mntopts
Comma-separated list of mount options to use when mounting datasets within the
pool.
See
.Xr zfs 8
for a description of dataset properties and mount options.
.It Fl o Ar property Ns = Ns Ar value
Sets the specified property on the imported pool.
See the
.Sx Properties
section for more information on the available pool properties.
.It Fl R Ar root
Sets the
.Sy cachefile
property to
.Sy none
and the
.Sy altroot
property to
.Ar root .
.El
.It Xo
.Nm
.Cm import
.Op Fl Dfmt
.Op Fl F Op Fl n
.Op Fl -rewind-to-checkpoint
.Op Fl c Ar cachefile Ns | Ns Fl d Ar dir
.Op Fl o Ar mntopts
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Op Fl R Ar root
.Ar pool Ns | Ns Ar id
.Op Ar newpool
.Xc
Imports a specific pool.
A pool can be identified by its name or the numeric identifier.
If
.Ar newpool
is specified, the pool is imported using the name
.Ar newpool .
Otherwise, it is imported with the same name as its exported name.
.Pp
If a device is removed from a system without running
.Nm zpool Cm export
first, the device appears as potentially active.
It cannot be determined if this was a failed export, or whether the device is
really in use from another host.
To import a pool in this state, the
.Fl f
option is required.
.Bl -tag -width Ds
.It Fl c Ar cachefile
Reads configuration from the given
.Ar cachefile
that was created with the
.Sy cachefile
pool property.
This
.Ar cachefile
is used instead of searching for devices.
.It Fl d Ar dir
Searches for devices or files in
.Ar dir .
The
.Fl d
option can be specified multiple times.
This option is incompatible with the
.Fl c
option.
.It Fl D
Imports destroyed pool.
The
.Fl f
option is also required.
.It Fl f
Forces import, even if the pool appears to be potentially active.
.It Fl F
Recovery mode for a non-importable pool.
Attempt to return the pool to an importable state by discarding the last few
transactions.
Not all damaged pools can be recovered by using this option.
If successful, the data from the discarded transactions is irretrievably lost.
This option is ignored if the pool is importable or already imported.
.It Fl l
Indicates that the zpool command will request encryption keys for all
encrypted datasets it attempts to mount as it is bringing the pool
online.
This is equivalent to running
.Nm Cm mount
on each encrypted dataset immediately after the pool is imported.
If any datasets have a
.Sy prompt
keysource this command will block waiting for the key to be entered.
Otherwise, encrypted datasets will be left unavailable until the keys are
loaded.
.It Fl m
Allows a pool to import when there is a missing log device.
Recent transactions can be lost because the log device will be discarded.
.It Fl n
Used with the
.Fl F
recovery option.
Determines whether a non-importable pool can be made importable again, but does
not actually perform the pool recovery.
For more details about pool recovery mode, see the
.Fl F
option, above.
.It Fl o Ar mntopts
Comma-separated list of mount options to use when mounting datasets within the
pool.
See
.Xr zfs 8
for a description of dataset properties and mount options.
.It Fl o Ar property Ns = Ns Ar value
Sets the specified property on the imported pool.
See the
.Sx Properties
section for more information on the available pool properties.
.It Fl R Ar root
Sets the
.Sy cachefile
property to
.Sy none
and the
.Sy altroot
property to
.Ar root .
.It Fl t
Used with
.Ar newpool .
Specifies that
.Ar newpool
is temporary.
Temporary pool names last until export.
Ensures that the original pool name will be used in all label updates and
therefore is retained upon export.
Will also set
.Sy cachefile
property to
.Sy none
when not explicitly specified.
.It Fl -rewind-to-checkpoint
Rewinds pool to the checkpointed state.
Once the pool is imported with this flag there is no way to undo the rewind.
All changes and data that were written after the checkpoint are lost!
The only exception is when the
.Sy readonly
mounting option is enabled.
In this case, the checkpointed state of the pool is opened and an
administrator can see how the pool would look like if they were
to fully rewind.
.El
.It Xo
.Nm
.Cm initialize
.Op Fl c | Fl s
.Ar pool
.Op Ar device Ns ...
.Xc
Begins initializing by writing to all unallocated regions on the specified
devices, or all eligible devices in the pool if no individual devices are
specified.
Only leaf data or log devices may be initialized.
.Bl -tag -width Ds
.It Fl c, -cancel
Cancel initializing on the specified devices, or all eligible devices if none
are specified.
If one or more target devices are invalid or are not currently being
initialized, the command will fail and no cancellation will occur on any device.
.It Fl s -suspend
Suspend initializing on the specified devices, or all eligible devices if none
are specified.
If one or more target devices are invalid or are not currently being
initialized, the command will fail and no suspension will occur on any device.
Initializing can then be resumed by running
.Nm zpool Cm initialize
with no flags on the relevant target devices.
.El
.It Xo
.Nm
.Cm iostat
.Op Oo Fl lq Oc | Ns Fl rw
.Op Fl T Sy u Ns | Ns Sy d
.Op Fl ghHLnpPvy
.Oo Oo Ar pool Ns ... Oc Ns | Ns Oo Ar pool vdev Ns ... Oc Ns | Ns Oo Ar vdev Ns ... Oc Oc
.Op Ar interval Op Ar count
.Xc
Displays I/O statistics for the given pools/vdevs.
Physical I/Os may be observed via
.Xr iostat 8 .
If writes are located nearby, they may be merged into a single larger operation.
Additional I/O may be generated depending on the level of vdev redundancy.
To filter output, you may pass in a list of pools, a pool and list of vdevs
in that pool, or a list of any vdevs from any pool.
If no items are specified, statistics for every pool in the system are shown.
When given an
.Ar interval ,
the statistics are printed every
.Ar interval
seconds until ^C is pressed.
If
.Fl n
flag is specified the headers are displayed only once, otherwise they are
displayed periodically.
If
.Ar count
is specified, the command exits after
.Ar count
reports are printed.
The first report printed is always the statistics since boot regardless of
whether
.Ar interval
and
.Ar count
are passed.
Also note that the units of
.Sy K ,
.Sy M ,
.Sy G ...
that are printed in the report are in base 1024.
To get the raw values, use the
.Fl p
flag.
.Bl -tag -width Ds
.It Fl T Sy u Ns | Ns Sy d
Display a time stamp.
Specify
.Sy u
for a printed representation of the internal representation of time.
See
.Xr time 2 .
Specify
.Sy d
for standard date format.
See
.Xr date 1 .
.It Fl i
Display vdev initialization status.
.It Fl g
Display vdev GUIDs instead of the normal device names.
These GUIDs can be used in place of device names for the zpool
detach/offline/remove/replace commands.
.It Fl H
Scripted mode.
Do not display headers, and separate fields by a single tab instead of
arbitrary space.
.It Fl L
Display real paths for vdevs resolving all symbolic links.
This can be used to look up the current block device name regardless of the
.Pa /dev/dsk/
path used to open it.
.It Fl n
Print headers only once when passed.
.It Fl p
Display numbers in parsable (exact) values.
Time values are in nanoseconds.
.It Fl P
Display full paths for vdevs instead of only the last component of
the path.
This can be used in conjunction with the
.Fl L
flag.
.It Fl r
Print request size histograms for the leaf vdev's IO
This includes histograms of individual IOs (ind) and aggregate IOs (agg).
These stats can be useful for observing how well IO aggregation is working.
Note that TRIM IOs may exceed 16M, but will be counted as 16M.
.It Fl v
Verbose statistics Reports usage statistics for individual vdevs within the
pool, in addition to the pool-wide statistics.
.It Fl y
Omit statistics since boot.
Normally the first line of output reports the statistics since boot.
This option suppresses that first line of output.
.Ar interval
.It Fl w
Display latency histograms:
.Pp
.Ar total_wait :
Total IO time (queuing + disk IO time).
.Ar disk_wait :
Disk IO time (time reading/writing the disk).
.Ar syncq_wait :
Amount of time IO spent in synchronous priority queues.
Does not include disk time.
.Ar asyncq_wait :
Amount of time IO spent in asynchronous priority queues.
Does not include disk time.
.Ar scrub :
Amount of time IO spent in scrub queue.
Does not include disk time.
.It Fl l
Include average latency statistics:
.Pp
.Ar total_wait :
Average total IO time (queuing + disk IO time).
.Ar disk_wait :
Average disk IO time (time reading/writing the disk).
.Ar syncq_wait :
Average amount of time IO spent in synchronous priority queues.
Does not include disk time.
.Ar asyncq_wait :
Average amount of time IO spent in asynchronous priority queues.
Does not include disk time.
.Ar scrub :
Average queuing time in scrub queue.
Does not include disk time.
.Ar trim :
Average queuing time in trim queue.
Does not include disk time.
.It Fl q
Include active queue statistics.
Each priority queue has both pending (
.Ar pend )
and active (
.Ar activ )
IOs.
Pending IOs are waiting to be issued to the disk, and active IOs have been
issued to disk and are waiting for completion.
These stats are broken out by priority queue:
.Pp
.Ar syncq_read/write :
Current number of entries in synchronous priority
queues.
.Ar asyncq_read/write :
Current number of entries in asynchronous priority queues.
.Ar scrubq_read :
Current number of entries in scrub queue.
.Ar trimq_write :
Current number of entries in trim queue.
.Pp
All queue statistics are instantaneous measurements of the number of
entries in the queues.
If you specify an interval, the measurements will be sampled from the end of
the interval.
.El
.It Xo
.Nm
.Cm labelclear
.Op Fl f
.Ar device
.Xc
Removes ZFS label information from the specified
.Ar device .
The
.Ar device
must not be part of an active pool configuration.
.Bl -tag -width Ds
.It Fl f
Treat exported or foreign devices as inactive.
.El
.It Xo
.Nm
.Cm list
.Op Fl HgLpPv
.Op Fl o Ar property Ns Oo , Ns Ar property Oc Ns ...
.Op Fl T Sy u Ns | Ns Sy d
.Oo Ar pool Oc Ns ...
.Op Ar interval Op Ar count
.Xc
Lists the given pools along with a health status and space usage.
If no
.Ar pool Ns s
are specified, all pools in the system are listed.
When given an
.Ar interval ,
the information is printed every
.Ar interval
seconds until ^C is pressed.
If
.Ar count
is specified, the command exits after
.Ar count
reports are printed.
.Bl -tag -width Ds
.It Fl g
Display vdev GUIDs instead of the normal device names.
These GUIDs can be used in place of device names for the zpool
detach/offline/remove/replace commands.
.It Fl H
Scripted mode.
Do not display headers, and separate fields by a single tab instead of arbitrary
space.
.It Fl o Ar property
Comma-separated list of properties to display.
See the
.Sx Properties
section for a list of valid properties.
The default list is
.Cm name , size , allocated , free , checkpoint, expandsize , fragmentation , capacity ,
.Cm dedupratio , health , altroot .
.It Fl L
Display real paths for vdevs resolving all symbolic links.
This can be used to look up the current block device name regardless of the
/dev/disk/ path used to open it.
.It Fl p
Display numbers in parsable
.Pq exact
values.
.It Fl P
Display full paths for vdevs instead of only the last component of
the path.
This can be used in conjunction with the
.Fl L
flag.
.It Fl T Sy u Ns | Ns Sy d
Display a time stamp.
Specify
.Sy u
for a printed representation of the internal representation of time.
See
.Xr time 2 .
Specify
.Sy d
for standard date format.
See
.Xr date 1 .
.It Fl v
Verbose statistics.
Reports usage statistics for individual vdevs within the pool, in addition to
the pool-wise statistics.
.El
.It Xo
.Nm
.Cm offline
.Op Fl t
.Ar pool Ar device Ns ...
.Xc
Takes the specified physical device offline.
While the
.Ar device
is offline, no attempt is made to read or write to the device.
This command is not applicable to spares.
.Bl -tag -width Ds
.It Fl t
Temporary.
Upon reboot, the specified physical device reverts to its previous state.
.El
.It Xo
.Nm
.Cm online
.Op Fl e
.Ar pool Ar device Ns ...
.Xc
Brings the specified physical device online.
This command is not applicable to spares.
.Bl -tag -width Ds
.It Fl e
Expand the device to use all available space.
If the device is part of a mirror or raidz then all devices must be expanded
before the new space will become available to the pool.
.El
.It Xo
.Nm
.Cm reguid
.Ar pool
.Xc
Generates a new unique identifier for the pool.
You must ensure that all devices in this pool are online and healthy before
performing this action.
.It Xo
.Nm
.Cm reopen
.Ar pool
.Xc
Reopen all the vdevs associated with the pool.
.It Xo
.Nm
.Cm remove
.Op Fl np
.Ar pool Ar device Ns ...
.Xc
Removes the specified device from the pool.
This command currently only supports removing hot spares, cache, log
devices and mirrored top-level vdevs (mirror of leaf devices); but not raidz.
.sp
Removing a top-level vdev reduces the total amount of space in the storage pool.
The specified device will be evacuated by copying all allocated space from it to
the other devices in the pool.
In this case, the
.Nm zpool Cm remove
command initiates the removal and returns, while the evacuation continues in
the background.
The removal progress can be monitored with
.Nm zpool Cm status.
This feature must be enabled to be used, see
.Xr zpool-features 7
.Pp
A mirrored top-level device (log or data) can be removed by specifying the top-level mirror for the
same.
Non-log devices or data devices that are part of a mirrored configuration can be removed using
the
.Nm zpool Cm detach
command.
.Bl -tag -width Ds
.It Fl n
Do not actually perform the removal ("no-op").
Instead, print the estimated amount of memory that will be used by the
mapping table after the removal completes.
This is nonzero only for top-level vdevs.
.El
.Bl -tag -width Ds
.It Fl p
Used in conjunction with the
.Fl n
flag, displays numbers as parsable (exact) values.
.El
.It Xo
.Nm
.Cm remove
.Fl s
.Ar pool
.Xc
Stops and cancels an in-progress removal of a top-level vdev.
.It Xo
.Nm
.Cm replace
.Op Fl f
.Ar pool Ar device Op Ar new_device
.Xc
Replaces
.Ar old_device
with
.Ar new_device .
This is equivalent to attaching
.Ar new_device ,
waiting for it to resilver, and then detaching
.Ar old_device .
.Pp
The size of
.Ar new_device
must be greater than or equal to the minimum size of all the devices in a mirror
or raidz configuration.
.Pp
.Ar new_device
is required if the pool is not redundant.
If
.Ar new_device
is not specified, it defaults to
.Ar old_device .
This form of replacement is useful after an existing disk has failed and has
been physically replaced.
In this case, the new disk may have the same
.Pa /dev/dsk
path as the old device, even though it is actually a different disk.
ZFS recognizes this.
.Bl -tag -width Ds
.It Fl f
Forces use of
.Ar new_device ,
even if its appears to be in use.
Not all devices can be overridden in this manner.
.El
.It Xo
.Nm
.Cm resilver
.Ar pool Ns ...
.Xc
Starts a resilver.
If an existing resilver is already running it will be restarted from the
beginning.
Any drives that were scheduled for a deferred resilver will be added to the
new one.
This requires the
.Sy resilver_defer
feature.
.It Xo
.Nm
.Cm scrub
.Op Fl s | Fl p
.Ar pool Ns ...
.Xc
Begins a scrub or resumes a paused scrub.
The scrub examines all data in the specified pools to verify that it checksums
correctly.
For replicated
.Pq mirror or raidz
devices, ZFS automatically repairs any damage discovered during the scrub.
The
.Nm zpool Cm status
command reports the progress of the scrub and summarizes the results of the
scrub upon completion.
.Pp
Scrubbing and resilvering are very similar operations.
The difference is that resilvering only examines data that ZFS knows to be out
of date
.Po
for example, when attaching a new device to a mirror or replacing an existing
device
.Pc ,
whereas scrubbing examines all data to discover silent errors due to hardware
faults or disk failure.
.Pp
Because scrubbing and resilvering are I/O-intensive operations, ZFS only allows
one at a time.
If a scrub is paused, the
.Nm zpool Cm scrub
resumes it.
If a resilver is in progress, ZFS does not allow a scrub to be started until the
resilver completes.
.Pp
Note that, due to changes in pool data on a live system, it is possible for
scrubs to progress slightly beyond 100% completion.
During this period, no completion time estimate will be provided.
.Bl -tag -width Ds
.It Fl s
Stop scrubbing.
.El
.Bl -tag -width Ds
.It Fl p
Pause scrubbing.
Scrub pause state and progress are periodically synced to disk.
If the system is restarted or pool is exported during a paused scrub,
even after import, scrub will remain paused until it is resumed.
Once resumed the scrub will pick up from the place where it was last
checkpointed to disk.
To resume a paused scrub issue
.Nm zpool Cm scrub
again.
.El
.It Xo
.Nm
.Cm set
.Ar property Ns = Ns Ar value
.Ar pool
.Xc
Sets the given property on the specified pool.
See the
.Sx Properties
section for more information on what properties can be set and acceptable
values.
.It Xo
.Nm
.Cm split
.Op Fl gLlnP
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Op Fl R Ar root
.Ar pool newpool
.Xc
Splits devices off
.Ar pool
creating
.Ar newpool .
All vdevs in
.Ar pool
must be mirrors.
At the time of the split,
.Ar newpool
will be a replica of
.Ar pool .
.Bl -tag -width Ds
.It Fl g
Display vdev GUIDs instead of the normal device names.
These GUIDs can be used in place of device names for the zpool
detach/offline/remove/replace commands.
.It Fl L
Display real paths for vdevs resolving all symbolic links.
This can be used to look up the current block device name regardless of the
.Pa /dev/disk/
path used to open it.
.It Fl l
Indicates that this command will request encryption keys for all encrypted
datasets it attempts to mount as it is bringing the new pool online.
Note that if any datasets have a
.Sy keylocation
of
.Sy prompt
this command will block waiting for the keys to be entered.
Without this flag encrypted datasets will be left unavailable and unmounted
until the keys are loaded.
.It Fl n
Do dry run, do not actually perform the split.
Print out the expected configuration of
.Ar newpool .
.It Fl P
Display full paths for vdevs instead of only the last component of
the path.
This can be used in conjunction with the
.Fl L
flag.
.It Fl o Ar property Ns = Ns Ar value
Sets the specified property for
.Ar newpool .
See the
.Sx Properties
section for more information on the available pool properties.
.It Fl R Ar root
Set
.Sy altroot
for
.Ar newpool
to
.Ar root
and automatically import it.
.El
.It Xo
.Nm
.Cm status
.Op Fl DigLpPstvx
.Op Fl T Sy u Ns | Ns Sy d
.Oo Ar pool Oc Ns ...
.Op Ar interval Op Ar count
.Xc
Displays the detailed health status for the given pools.
If no
.Ar pool
is specified, then the status of each pool in the system is displayed.
For more information on pool and device health, see the
.Sx Device Failure and Recovery
section.
.Pp
If a scrub or resilver is in progress, this command reports the percentage done
and the estimated time to completion.
Both of these are only approximate, because the amount of data in the pool and
the other workloads on the system can change.
.Bl -tag -width Ds
.It Fl D
Display a histogram of deduplication statistics, showing the allocated
.Pq physically present on disk
and referenced
.Pq logically referenced in the pool
block counts and sizes by reference count.
.It Fl g
Display vdev GUIDs instead of the normal device names.
These GUIDs can be used in place of device names for the zpool
detach/offline/remove/replace commands.
.It Fl L
Display real paths for vdevs resolving all symbolic links.
This can be used to look up the current block device name regardless of the
.Pa /dev/disk/
path used to open it.
.It Fl p
Display numbers in parsable (exact) values.
.It Fl P
Display full paths for vdevs instead of only the last component of
the path.
This can be used in conjunction with the
.Fl L
flag.
.It Fl s
Display the number of leaf VDEV slow IOs.
This is the number of IOs that didn't complete in
.Sy zio_slow_io_ms
milliseconds (default 30 seconds).
This does not necessarily mean the IOs failed to complete, just took an
unreasonably long amount of time.
This may indicate a problem with the underlying storage.
.It Fl t
Display vdev TRIM status.
.It Fl T Sy u Ns | Ns Sy d
Display a time stamp.
Specify
.Sy u
for a printed representation of the internal representation of time.
See
.Xr time 2 .
Specify
.Sy d
for standard date format.
See
.Xr date 1 .
.It Fl v
Displays verbose data error information, printing out a complete list of all
data errors since the last complete pool scrub.
.It Fl x
Only display status for pools that are exhibiting errors or are otherwise
unavailable.
Warnings about pools not using the latest on-disk format will not be included.
.El
.It Xo
.Nm
.Cm sync
.Oo Ar pool Oc Ns ...
.Xc
Forces all in-core dirty data to be written to the primary pool storage and
not the ZIL.
It will also update administrative information including quota reporting.
Without arguments,
.Nm zpool Cm sync
will sync all pools on the system.
Otherwise, it will only sync the specified
.Ar pool .
.It Xo
.Nm
.Cm trim
.Op Fl d
.Op Fl r Ar rate
.Op Fl c | Fl s
.Ar pool
.Op Ar device Ns ...
.Xc
Initiates an immediate on-demand TRIM operation for all of the free space in
a pool.
This operation informs the underlying storage devices of all blocks
in the pool which are no longer allocated and allows thinly provisioned
devices to reclaim the space.
.Pp
A manual on-demand TRIM operation can be initiated irrespective of the
.Sy autotrim
pool property setting.
See the documentation for the
.Sy autotrim
property above for the types of vdev devices which can be trimmed.
.Bl -tag -width Ds
.It Fl d -secure
Causes a secure TRIM to be initiated.
When performing a secure TRIM, the device guarantees that data stored on the
trimmed blocks has been erased.
This requires support from the device and is not supported by all SSDs.
.It Fl r -rate Ar rate
Controls the rate at which the TRIM operation progresses.
Without this option TRIM is executed as quickly as possible.
The rate, expressed in bytes per second, is applied on a per-vdev basis and
may be set differently for each leaf vdev.
.It Fl c, -cancel
Cancel trimming on the specified devices, or all eligible devices if none
are specified.
If one or more target devices are invalid or are not currently being
trimmed, the command will fail and no cancellation will occur on any device.
.It Fl s -suspend
Suspend trimming on the specified devices, or all eligible devices if none
are specified.
If one or more target devices are invalid or are not currently being
trimmed, the command will fail and no suspension will occur on any device.
Trimming can then be resumed by running
.Nm zpool Cm trim
with no flags on the relevant target devices.
.El
.It Xo
.Nm
.Cm upgrade
.Xc
Displays pools which do not have all supported features enabled and pools
formatted using a legacy ZFS version number.
These pools can continue to be used, but some features may not be available.
Use
.Nm zpool Cm upgrade Fl a
to enable all features on all pools.
.It Xo
.Nm
.Cm upgrade
.Fl v
.Xc
Displays legacy ZFS versions supported by the current software.
See
.Xr zpool-features 7
for a description of feature flags features supported by the current software.
.It Xo
.Nm
.Cm upgrade
.Op Fl V Ar version
.Fl a Ns | Ns Ar pool Ns ...
.Xc
Enables all supported features on the given pool.
Once this is done, the pool will no longer be accessible on systems that do not
support feature flags.
See
.Xr zpool-features 7
for details on compatibility with systems that support feature flags, but do not
support all features enabled on the pool.
.Bl -tag -width Ds
.It Fl a
Enables all supported features on all pools.
.It Fl V Ar version
Upgrade to the specified legacy version.
If the
.Fl V
flag is specified, no features will be enabled on the pool.
This option can only be used to increase the version number up to the last
supported legacy version number.
.El
.El
.Sh EXIT STATUS
The following exit values are returned:
.Bl -tag -width Ds
.It Sy 0
Successful completion.
.It Sy 1
An error occurred.
.It Sy 2
Invalid command line options were specified.
.El
.Sh EXAMPLES
.Bl -tag -width Ds
.It Sy Example 1 No Creating a RAID-Z Storage Pool
The following command creates a pool with a single raidz root vdev that
consists of six disks.
.Bd -literal
# zpool create tank raidz c0t0d0 c0t1d0 c0t2d0 c0t3d0 c0t4d0 c0t5d0
.Ed
.It Sy Example 2 No Creating a Mirrored Storage Pool
The following command creates a pool with two mirrors, where each mirror
contains two disks.
.Bd -literal
# zpool create tank mirror c0t0d0 c0t1d0 mirror c0t2d0 c0t3d0
.Ed
.It Sy Example 3 No Creating a ZFS Storage Pool by Using Slices
The following command creates an unmirrored pool using two disk slices.
.Bd -literal
# zpool create tank /dev/dsk/c0t0d0s1 c0t1d0s4
.Ed
.It Sy Example 4 No Creating a ZFS Storage Pool by Using Files
The following command creates an unmirrored pool using files.
While not recommended, a pool based on files can be useful for experimental
purposes.
.Bd -literal
# zpool create tank /path/to/file/a /path/to/file/b
.Ed
.It Sy Example 5 No Adding a Mirror to a ZFS Storage Pool
The following command adds two mirrored disks to the pool
.Em tank ,
assuming the pool is already made up of two-way mirrors.
The additional space is immediately available to any datasets within the pool.
.Bd -literal
# zpool add tank mirror c1t0d0 c1t1d0
.Ed
.It Sy Example 6 No Listing Available ZFS Storage Pools
The following command lists all available pools on the system.
In this case, the pool
.Em zion
is faulted due to a missing device.
The results from this command are similar to the following:
.Bd -literal
# zpool list
NAME    SIZE  ALLOC   FREE   FRAG  EXPANDSZ    CAP  DEDUP  HEALTH  ALTROOT
rpool  19.9G  8.43G  11.4G    33%         -    42%  1.00x  ONLINE  -
tank   61.5G  20.0G  41.5G    48%         -    32%  1.00x  ONLINE  -
zion       -      -      -      -         -      -      -  FAULTED -
.Ed
.It Sy Example 7 No Destroying a ZFS Storage Pool
The following command destroys the pool
.Em tank
and any datasets contained within.
.Bd -literal
# zpool destroy -f tank
.Ed
.It Sy Example 8 No Exporting a ZFS Storage Pool
The following command exports the devices in pool
.Em tank
so that they can be relocated or later imported.
.Bd -literal
# zpool export tank
.Ed
.It Sy Example 9 No Importing a ZFS Storage Pool
The following command displays available pools, and then imports the pool
.Em tank
for use on the system.
The results from this command are similar to the following:
.Bd -literal
# zpool import
  pool: tank
    id: 15451357997522795478
 state: ONLINE
action: The pool can be imported using its name or numeric identifier.
config:

        tank        ONLINE
          mirror    ONLINE
            c1t2d0  ONLINE
            c1t3d0  ONLINE

# zpool import tank
.Ed
.It Sy Example 10 No Upgrading All ZFS Storage Pools to the Current Version
The following command upgrades all ZFS Storage pools to the current version of
the software.
.Bd -literal
# zpool upgrade -a
This system is currently running ZFS version 2.
.Ed
.It Sy Example 11 No Managing Hot Spares
The following command creates a new pool with an available hot spare:
.Bd -literal
# zpool create tank mirror c0t0d0 c0t1d0 spare c0t2d0
.Ed
.Pp
If one of the disks were to fail, the pool would be reduced to the degraded
state.
The failed device can be replaced using the following command:
.Bd -literal
# zpool replace tank c0t0d0 c0t3d0
.Ed
.Pp
Once the data has been resilvered, the spare is automatically removed and is
made available for use should another device fail.
The hot spare can be permanently removed from the pool using the following
command:
.Bd -literal
# zpool remove tank c0t2d0
.Ed
.It Sy Example 12 No Creating a ZFS Pool with Mirrored Separate Intent Logs
The following command creates a ZFS storage pool consisting of two, two-way
mirrors and mirrored log devices:
.Bd -literal
# zpool create pool mirror c0d0 c1d0 mirror c2d0 c3d0 log mirror \e
  c4d0 c5d0
.Ed
.It Sy Example 13 No Adding Cache Devices to a ZFS Pool
The following command adds two disks for use as cache devices to a ZFS storage
pool:
.Bd -literal
# zpool add pool cache c2d0 c3d0
.Ed
.Pp
Once added, the cache devices gradually fill with content from main memory.
Depending on the size of your cache devices, it could take over an hour for
them to fill.
Capacity and reads can be monitored using the
.Cm iostat
option as follows:
.Bd -literal
# zpool iostat -v pool 5
.Ed
.It Sy Example 14 No Removing a Mirrored top-level (Log or Data) Device
The following commands remove the mirrored log device
.Sy mirror-2
and mirrored top-level data device
.Sy mirror-1 .
.Pp
Given this configuration:
.Bd -literal
  pool: tank
 state: ONLINE
 scrub: none requested
config:

         NAME        STATE     READ WRITE CKSUM
         tank        ONLINE       0     0     0
           mirror-0  ONLINE       0     0     0
             c6t0d0  ONLINE       0     0     0
             c6t1d0  ONLINE       0     0     0
           mirror-1  ONLINE       0     0     0
             c6t2d0  ONLINE       0     0     0
             c6t3d0  ONLINE       0     0     0
         logs
           mirror-2  ONLINE       0     0     0
             c4t0d0  ONLINE       0     0     0
             c4t1d0  ONLINE       0     0     0
.Ed
.Pp
The command to remove the mirrored log
.Sy mirror-2
is:
.Bd -literal
# zpool remove tank mirror-2
.Ed
.Pp
The command to remove the mirrored data
.Sy mirror-1
is:
.Bd -literal
# zpool remove tank mirror-1
.Ed
.It Sy Example 15 No Displaying expanded space on a device
The following command displays the detailed information for the pool
.Em data .
This pool is comprised of a single raidz vdev where one of its devices
increased its capacity by 10GB.
In this example, the pool will not be able to utilize this extra capacity until
all the devices under the raidz vdev have been expanded.
.Bd -literal
# zpool list -v data
NAME         SIZE  ALLOC   FREE   FRAG  EXPANDSZ    CAP  DEDUP  HEALTH  ALTROOT
data        23.9G  14.6G  9.30G    48%         -    61%  1.00x  ONLINE  -
  raidz1    23.9G  14.6G  9.30G    48%         -
    c1t1d0      -      -      -      -         -
    c1t2d0      -      -      -      -       10G
    c1t3d0      -      -      -      -         -
.Ed
.El
.Sh ENVIRONMENT VARIABLES
.Bl -tag -width "ZPOOL_VDEV_NAME_GUID"
.It Ev ZPOOL_VDEV_NAME_GUID
Cause
.Nm zpool subcommands to output vdev guids by default.
This behavior is identical to the
.Nm zpool status -g
command line option.
.El
.Bl -tag -width "ZPOOL_VDEV_NAME_FOLLOW_LINKS"
.It Ev ZPOOL_VDEV_NAME_FOLLOW_LINKS
Cause
.Nm zpool
subcommands to follow links for vdev names by default.
This behavior is identical to the
.Nm zpool status -L
command line option.
.El
.Bl -tag -width "ZPOOL_VDEV_NAME_PATH"
.It Ev ZPOOL_VDEV_NAME_PATH
Cause
.Nm zpool
subcommands to output full vdev path names by default.
This behavior is identical to the
.Nm zpool status -P
command line option.
.El
.Sh INTERFACE STABILITY
.Sy Evolving
.Sh SEE ALSO
.Xr attributes 7 ,
.Xr zpool-features 7 ,
.Xr zfs 8