ZPOOL(1M) Maintenance Commands ZPOOL(1M)

NAME


zpool - configure ZFS storage pools

SYNOPSIS


zpool -?
zpool add [-fn] pool vdev...
zpool attach [-f] pool device new_device
zpool checkpoint [-d, --discard] pool
zpool clear pool [device]
zpool create [-dfn] [-B] [-m mountpoint] [-o property=value]...
[-O file-system-property=value]... [-R root] pool vdev...
zpool destroy [-f] pool
zpool detach pool device
zpool export [-f] pool...
zpool get [-Hp] [-o field[,field]...] all|property[,property]... pool...
zpool history [-il] [pool]...
zpool import [-D] [-d dir]
zpool import -a [-DfmN] [-F [-n]] [-c cachefile|-d dir] [-o mntopts]
[-o property=value]... [-R root]
zpool import [-Dfm] [-F [-n]] [--rewind-to-checkpoint]
[-c cachefile|-d dir] [-o mntopts] [-o property=value]... [-R root]
pool|id [newpool]
zpool initialize [-cs] pool [device...]
zpool iostat [-v] [-T u|d] [pool]... [interval [count]]
zpool labelclear [-f] device
zpool list [-Hpv] [-o property[,property]...] [-T u|d] [pool]...
[interval [count]]
zpool offline [-t] pool device...
zpool online [-e] pool device...
zpool reguid pool
zpool reopen pool
zpool remove [-np] pool device...
zpool remove -s pool
zpool replace [-f] pool device [new_device]
zpool scrub [-s | -p] pool...
zpool set property=value pool
zpool split [-n] [-o property=value]... [-R root] pool newpool
zpool status [-Dvx] [-T u|d] [pool]... [interval [count]]
zpool upgrade
zpool upgrade -v
zpool upgrade [-V version] -a|pool...

DESCRIPTION


The zpool 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 zfs(1M) for information on managing datasets.

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:

disk A block device, typically located under /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 (the relative portion of the
path under /dev/dsk). A whole disk can be specified by omitting
the slice or partition designation. For example, c0t0d0 is
equivalent to /dev/dsk/c0t0d0s2. When given a whole disk, ZFS
automatically labels the disk, if necessary.

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.

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.

raidz, raidz1, raidz2, raidz3
A variation on RAID-5 that allows for better distribution of parity
and eliminates the RAID-5 "write hole" (in which data and parity
become inconsistent after a power loss). Data and parity is
striped across all disks within a raidz group.

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 raidz1 vdev type
specifies a single-parity raidz group; the raidz2 vdev type
specifies a double-parity raidz group; and the raidz3 vdev type
specifies a triple-parity raidz group. The raidz vdev type is an
alias for raidz1.

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.

spare A special pseudo-vdev which keeps track of available hot spares for
a pool. For more information, see the Hot Spares section.

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 Intent
Log section.

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 Cache Devices section.

Virtual devices cannot be nested, so a mirror or raidz virtual device can
only contain files or disks. Mirrors of mirrors (or other combinations)
are not allowed.

A pool can have any number of virtual devices at the top of the
configuration (known as "root vdevs"). 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.

Virtual devices are specified one at a time on the command line, separated
by whitespace. The keywords mirror and 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:

# zpool create mypool mirror c0t0d0 c0t1d0 mirror c1t0d0 c1t1d0

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.

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.

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.

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:

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.

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:

+o 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.

+o 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.

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.

One or more component devices is in the faulted state, and
insufficient replicas exist to continue functioning. The
underlying conditions are as follows:

+o The device could be opened, but the contents did not match
expected values.

+o The number of I/O errors exceeds acceptable levels and the
device is faulted to prevent further use of the device.

OFFLINE The device was explicitly taken offline by the zpool offline
command.

ONLINE The device is online and functioning.

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.

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.

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.

Hot Spares


ZFS allows devices to be associated with pools as "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 spare vdev with any number of devices. For example,

# zpool create pool mirror c0d0 c1d0 spare c2d0 c3d0

Spares can be shared across multiple pools, and can be added with the zpool
add command and removed with the zpool remove command. Once a spare
replacement is initiated, a new 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.

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.

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.

Spares cannot replace log devices.

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 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:

# zpool create pool c0d0 c1d0 log c2d0

Multiple log devices can also be specified, and they can be mirrored. See
the EXAMPLES section for an example of mirroring multiple log devices.

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.

Cache Devices


Devices can be added to a storage pool as "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.

To create a pool with cache devices, specify a cache vdev with any number
of devices. For example:

# zpool create pool c0d0 c1d0 cache c2d0 c3d0

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.

The content of the cache devices is considered volatile, as is the case
with other system caches.

Pool checkpoint


Before starting critical procedures that include destructive actions (e.g
zfs 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. Otherwise, the checkpoint can be discarded when the procedure
has completed successfully.

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.

To create a checkpoint for a pool:

# zpool checkpoint pool

To later rewind to its checkpointed state, you need to first export it and
then rewind it during import:

# zpool export pool
# zpool import --rewind-to-checkpoint pool

To discard the checkpoint from a pool:

# zpool checkpoint -d pool

Dataset reservations (controlled by the reservation or 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.

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.

The following are read-only properties:

allocated
Amount of storage space used within the pool.

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 -B option.

capacity
Percentage of pool space used. This property can also be referred
to by its shortened column name, cap.

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 (e.g, using zpool online -e). This space
occurs when a LUN is dynamically expanded.

fragmentation
The amount of fragmentation in the pool.

free The amount of free space available in the pool.

freeing
After a file system or snapshot is destroyed, the space it was
using is returned to the pool asynchronously. freeing is the
amount of space remaining to be reclaimed. Over time freeing will
decrease while free increases.

health The current health of the pool. Health can be one of ONLINE,
DEGRADED, FAULTED, OFFLINE, REMOVED, UNAVAIL.

guid A unique identifier for the pool.

size Total size of the storage pool.

unsupported@feature_guid
Information about unsupported features that are enabled on the
pool. See zpool-features(5) for details.

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 zfs(1M) command takes into account, but the zpool
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.

The following property can be set at creation time and import time:

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.
altroot is not a persistent property. It is valid only while the
system is up. Setting altroot defaults to using cachefile=none,
though this may be overridden using an explicit setting.

The following property can be set only at import time:

readonly=on|off
If set to on, the pool will be imported in read-only mode. This
property can also be referred to by its shortened column name,
rdonly.

The following properties can be set at creation time and import time, and
later changed with the zpool set command:

autoexpand=on|off
Controls automatic pool expansion when the underlying LUN is grown.
If set to 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 off. This property can also be referred to by its shortened
column name, expand.

autoreplace=on|off
Controls automatic device replacement. If set to off, device
replacement must be initiated by the administrator by using the
zpool replace command. If set to 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 off. This property can also be referred to by its
shortened column name, replace.

bootfs=pool/dataset
Identifies the default bootable dataset for the root pool. This
property is expected to be set mainly by the installation and
upgrade programs.

cachefile=path|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 zpool import -c. Setting it to the special value none creates
a temporary pool that is never cached, and the special value ""
(empty string) uses the default location.

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 cachefile is exported or destroyed, the file is
removed.

comment=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.

dedupditto=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 0 which causes no ditto copies to be created for
deduplicated blocks. The minimum legal nonzero setting is 100.

delegation=on|off
Controls whether a non-privileged user is granted access based on
the dataset permissions defined on the dataset. See zfs(1M) for
more information on ZFS delegated administration.

failmode=wait|continue|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:

wait Blocks all I/O access until the device connectivity is
recovered and the errors are cleared. This is the
default behavior.

continue Returns 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.

panic Prints out a message to the console and generates a
system crash dump.

feature@feature_name=enabled
The value of this property is the current state of feature_name.
The only valid value when setting this property is enabled which
moves feature_name to the enabled state. See zpool-features(5) for
details on feature states.

listsnapshots=on|off
Controls whether information about snapshots associated with this
pool is output when zfs list is run without the -t option. The
default value is off. This property can also be referred to by its
shortened name, listsnaps.

version=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 zpool 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.

Subcommands


All subcommands that modify state are logged persistently to the pool in
their original form.

The zpool 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:

zpool -?
Displays a help message.

zpool add [-fn] pool vdev...
Adds the specified virtual devices to the given pool. The vdev
specification is described in the Virtual Devices section. The
behavior of the -f option, and the device checks performed are
described in the zpool create subcommand.

-f Forces use of vdevs, even if they appear in use or specify
a conflicting replication level. Not all devices can be
overridden in this manner.

-n Displays the configuration that would be used without
actually adding the vdevs. The actual pool creation can
still fail due to insufficient privileges or device
sharing.

zpool attach [-f] pool device new_device
Attaches new_device to the existing device. The existing device
cannot be part of a raidz configuration. If device is not
currently part of a mirrored configuration, device automatically
transforms into a two-way mirror of device and new_device. If
device is part of a two-way mirror, attaching new_device creates a
three-way mirror, and so on. In either case, new_device begins to
resilver immediately.

-f Forces use of new_device, even if its appears to be in use.
Not all devices can be overridden in this manner.

zpool checkpoint [-d, --discard] pool
Checkpoints the current state of pool , which can be later restored
by zpool import --rewind-to-checkpoint. The existence of a
checkpoint in a pool prohibits the following zpool commands:
remove, attach, detach, split, and reguid. In addition, it may
break reservation boundaries if the pool lacks free space. The
zpool status command indicates the existence of a checkpoint or the
progress of discarding a checkpoint from a pool. The zpool list
command reports how much space the checkpoint takes from the pool.

-d, --discard
Discards an existing checkpoint from pool.

zpool clear pool [device]
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.

zpool create [-dfn] [-B] [-m mountpoint] [-o property=value]... [-O
file-system-property=value]... [-R root] pool vdev...
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
("_"), dash ("-"), and period ("."). The pool names mirror, raidz,
spare and log are reserved, as are names beginning with the pattern
c[0-9]. The vdev specification is described in the Virtual Devices
section.

The command verifies that each device specified is accessible and
not currently in use by another subsystem. 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 -f option.

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 -f is specified. The use of differently sized devices
within a single raidz or mirror group is also flagged as an error
unless -f is specified.

Unless the -R option is specified, the default mount point is
/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 -m option.

By default all supported features are enabled on the new pool
unless the -d option is specified.

-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 bootsize
property with the -o option. See the Properties section
for details.

-d Do not enable any features on the new pool. Individual
features can be enabled by setting their corresponding
properties to enabled with the -o option. See
zpool-features(5) for details about feature properties.

-f Forces use of vdevs, even if they appear in use or specify
a conflicting replication level. Not all devices can be
overridden in this manner.

-m mountpoint
Sets the mount point for the root dataset. The default
mount point is /pool or altroot/pool if altroot is
specified. The mount point must be an absolute path,
legacy, or none. For more information on dataset mount
points, see zfs(1M).

-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.

-o property=value
Sets the given pool properties. See the Properties section
for a list of valid properties that can be set.

-O file-system-property=value
Sets the given file system properties in the root file
system of the pool. See the Properties section of zfs(1M)
for a list of valid properties that can be set.

-R root
Equivalent to -o cachefile=none -o altroot=root

zpool destroy [-f] pool
Destroys the given pool, freeing up any devices for other use.
This command tries to unmount any active datasets before destroying
the pool.

-f Forces any active datasets contained within the pool to be
unmounted.

zpool detach pool device
Detaches device from a mirror. The operation is refused if there
are no other valid replicas of the data.

zpool export [-f] pool...
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 (even those of different
endianness) and imported as long as a sufficient number of devices
are present.

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.

For pools to be portable, you must give the zpool 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.

-f Forcefully unmount all datasets, using the unmount -f
command.

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.

zpool get [-Hp] [-o field[,field]...] all|property[,property]... pool...
Retrieves the given list of properties (or all properties if all is
used) for the specified storage pool(s). These properties are
displayed with the following fields:

name Name of storage pool
property Property name
value Property value
source Property source, either 'default' or 'local'.

See the Properties section for more information on the available
pool properties.

-H Scripted mode. Do not display headers, and separate fields
by a single tab instead of arbitrary space.

-o field
A comma-separated list of columns to display.
name,property,value,source is the default value.

-p Display numbers in parsable (exact) values.

zpool history [-il] [pool]...
Displays the command history of the specified pool(s) or all pools
if no pool is specified.

-i Displays internally logged ZFS events in addition to user
initiated events.

-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.

zpool import [-D] [-d dir]
Lists pools available to import. If the -d option is not
specified, this command searches for devices in /dev/dsk. The -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 zpool destroy
command, are not listed unless the -D option is specified.

The numeric identifier is unique, and can be used instead of the
pool name when multiple exported pools of the same name are
available.

-c cachefile
Reads configuration from the given cachefile that was
created with the cachefile pool property. This cachefile
is used instead of searching for devices.

-d dir Searches for devices or files in dir. The -d option can be
specified multiple times.

-D Lists destroyed pools only.

zpool import -a [-DfmN] [-F [-n]] [-c cachefile|-d dir] [-o mntopts] [-o
property=value]... [-R root]
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 zpool destroy command, will
not be imported unless the -D option is specified.

-a Searches for and imports all pools found.

-c cachefile
Reads configuration from the given cachefile that was
created with the cachefile pool property. This cachefile
is used instead of searching for devices.

-d dir Searches for devices or files in dir. The -d option can be
specified multiple times. This option is incompatible with
the -c option.

-D Imports destroyed pools only. The -f option is also
required.

-f Forces import, even if the pool appears to be potentially
active.

-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.

-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.

-n Used with the -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 -F option, above.

-N Import the pool without mounting any file systems.

-o mntopts
Comma-separated list of mount options to use when mounting
datasets within the pool. See zfs(1M) for a description of
dataset properties and mount options.

-o property=value
Sets the specified property on the imported pool. See the
Properties section for more information on the available
pool properties.

-R root
Sets the cachefile property to none and the altroot
property to root.

zpool import [-Dfm] [-F [-n]] [--rewind-to-checkpoint] [-c cachefile|-d
dir] [-o mntopts] [-o property=value]... [-R root] pool|id
[newpool]
Imports a specific pool. A pool can be identified by its name or
the numeric identifier. If newpool is specified, the pool is
imported using the name newpool. Otherwise, it is imported with
the same name as its exported name.

If a device is removed from a system without running zpool 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 -f option is required.

-c cachefile
Reads configuration from the given cachefile that was
created with the cachefile pool property. This cachefile
is used instead of searching for devices.

-d dir Searches for devices or files in dir. The -d option can be
specified multiple times. This option is incompatible with
the -c option.

-D Imports destroyed pool. The -f option is also required.

-f Forces import, even if the pool appears to be potentially
active.

-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.

-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.

-n Used with the -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 -F option, above.

-o mntopts
Comma-separated list of mount options to use when mounting
datasets within the pool. See zfs(1M) for a description of
dataset properties and mount options.

-o property=value
Sets the specified property on the imported pool. See the
Properties section for more information on the available
pool properties.

-R root
Sets the cachefile property to none and the altroot
property to root.

--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 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.

zpool initialize [-cs] pool [device...]
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.

-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.

-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 zpool initialize with no flags on the relevant
target devices.

zpool iostat [-v] [-T u|d] [pool]... [interval [count]]
Displays I/O statistics for the given pools. When given an
interval, the statistics are printed every interval seconds until
^C is pressed. If no pools are specified, statistics for every
pool in the system is shown. If count is specified, the command
exits after count reports are printed.

-T u|d Display a time stamp. Specify u for a printed
representation of the internal representation of time. See
time(2). Specify d for standard date format. See date(1).

-v Verbose statistics Reports usage statistics for individual
vdevs within the pool, in addition to the pool-wide
statistics.

zpool labelclear [-f] device
Removes ZFS label information from the specified device. The
device must not be part of an active pool configuration.

-f Treat exported or foreign devices as inactive.

zpool list [-Hpv] [-o property[,property]...] [-T u|d] [pool]... [interval
[count]]
Lists the given pools along with a health status and space usage.
If no pools are specified, all pools in the system are listed.
When given an interval, the information is printed every interval
seconds until ^C is pressed. If count is specified, the command
exits after count reports are printed.

-H Scripted mode. Do not display headers, and separate fields
by a single tab instead of arbitrary space.

-o property
Comma-separated list of properties to display. See the
Properties section for a list of valid properties. The
default list is name, size, allocated, free, checkpoint,
expandsize, fragmentation, capacity, dedupratio, health,
altroot.

-p Display numbers in parsable (exact) values.

-T u|d Display a time stamp. Specify -u for a printed
representation of the internal representation of time. See
time(2). Specify -d for standard date format. See
date(1).

-v Verbose statistics. Reports usage statistics for
individual vdevs within the pool, in addition to the pool-
wise statistics.

zpool offline [-t] pool device...
Takes the specified physical device offline. While the device is
offline, no attempt is made to read or write to the device. This
command is not applicable to spares.

-t Temporary. Upon reboot, the specified physical device
reverts to its previous state.

zpool online [-e] pool device...
Brings the specified physical device online. This command is not
applicable to spares.

-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.

zpool reguid pool
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.

zpool reopen pool
Reopen all the vdevs associated with the pool.

zpool remove [-np] pool device...
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.

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 zpool remove command initiates the removal and
returns, while the evacuation continues in the background. The
removal progress can be monitored with zpool status. This feature
must be enabled to be used, see zpool-features(5)

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 zpool detach command.

-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.

-p Used in conjunction with the -n flag, displays numbers as
parsable (exact) values.

zpool remove -s pool
Stops and cancels an in-progress removal of a top-level vdev.

zpool replace [-f] pool device [new_device]
Replaces old_device with new_device. This is equivalent to
attaching new_device, waiting for it to resilver, and then
detaching old_device.

The size of new_device must be greater than or equal to the minimum
size of all the devices in a mirror or raidz configuration.

new_device is required if the pool is not redundant. If new_device
is not specified, it defaults to 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 /dev/dsk path as the old device, even though it is actually a
different disk. ZFS recognizes this.

-f Forces use of new_device, even if its appears to be in use.
Not all devices can be overridden in this manner.

zpool scrub [-s | -p] pool...
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 (mirror or raidz) devices, ZFS automatically repairs
any damage discovered during the scrub. The zpool status command
reports the progress of the scrub and summarizes the results of the
scrub upon completion.

Scrubbing and resilvering are very similar operations. The
difference is that resilvering only examines data that ZFS knows to
be out of date (for example, when attaching a new device to a
mirror or replacing an existing device), whereas scrubbing examines
all data to discover silent errors due to hardware faults or disk
failure.

Because scrubbing and resilvering are I/O-intensive operations, ZFS
only allows one at a time. If a scrub is paused, the zpool scrub
resumes it. If a resilver is in progress, ZFS does not allow a
scrub to be started until the resilver completes.

-s Stop scrubbing.

-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 zpool
scrub again.

zpool set property=value pool
Sets the given property on the specified pool. See the Properties
section for more information on what properties can be set and
acceptable values.

zpool split [-n] [-o property=value]... [-R root] pool newpool
Splits devices off pool creating newpool. All vdevs in pool must
be mirrors. At the time of the split, newpool will be a replica of
pool.

-n Do dry run, do not actually perform the split. Print out
the expected configuration of newpool.

-o property=value
Sets the specified property for newpool. See the
Properties section for more information on the available
pool properties.

-R root
Set altroot for newpool to root and automatically import
it.

zpool status [-Dvx] [-T u|d] [pool]... [interval [count]]
Displays the detailed health status for the given pools. If no
pool is specified, then the status of each pool in the system is
displayed. For more information on pool and device health, see the
Device Failure and Recovery section.

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.

-D Display a histogram of deduplication statistics, showing
the allocated (physically present on disk) and referenced
(logically referenced in the pool) block counts and sizes
by reference count.

-T u|d Display a time stamp. Specify -u for a printed
representation of the internal representation of time. See
time(2). Specify -d for standard date format. See
date(1).

-v Displays verbose data error information, printing out a
complete list of all data errors since the last complete
pool scrub.

-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.

zpool upgrade
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
zpool upgrade -a to enable all features on all pools.

zpool upgrade -v
Displays legacy ZFS versions supported by the current software.
See zpool-features(5) for a description of feature flags features
supported by the current software.

zpool upgrade [-V version] -a|pool...
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 zpool-features(5) for details on
compatibility with systems that support feature flags, but do not
support all features enabled on the pool.

-a Enables all supported features on all pools.

-V version
Upgrade to the specified legacy version. If the -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.

EXIT STATUS


The following exit values are returned:

0 Successful completion.

1 An error occurred.

2 Invalid command line options were specified.

EXAMPLES


Example 1 Creating a RAID-Z Storage Pool
The following command creates a pool with a single raidz root vdev
that consists of six disks.

# zpool create tank raidz c0t0d0 c0t1d0 c0t2d0 c0t3d0 c0t4d0 c0t5d0

Example 2 Creating a Mirrored Storage Pool
The following command creates a pool with two mirrors, where each
mirror contains two disks.

# zpool create tank mirror c0t0d0 c0t1d0 mirror c0t2d0 c0t3d0

Example 3 Creating a ZFS Storage Pool by Using Slices
The following command creates an unmirrored pool using two disk
slices.

# zpool create tank /dev/dsk/c0t0d0s1 c0t1d0s4

Example 4 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.

# zpool create tank /path/to/file/a /path/to/file/b

Example 5 Adding a Mirror to a ZFS Storage Pool
The following command adds two mirrored disks to the pool tank,
assuming the pool is already made up of two-way mirrors. The
additional space is immediately available to any datasets within
the pool.

# zpool add tank mirror c1t0d0 c1t1d0

Example 6 Listing Available ZFS Storage Pools
The following command lists all available pools on the system. In
this case, the pool zion is faulted due to a missing device. The
results from this command are similar to the following:

# 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 -

Example 7 Destroying a ZFS Storage Pool
The following command destroys the pool tank and any datasets
contained within.

# zpool destroy -f tank

Example 8 Exporting a ZFS Storage Pool
The following command exports the devices in pool tank so that they
can be relocated or later imported.

# zpool export tank

Example 9 Importing a ZFS Storage Pool
The following command displays available pools, and then imports
the pool tank for use on the system. The results from this command
are similar to the following:

# 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

Example 10 Upgrading All ZFS Storage Pools to the Current Version
The following command upgrades all ZFS Storage pools to the current
version of the software.

# zpool upgrade -a
This system is currently running ZFS version 2.

Example 11 Managing Hot Spares
The following command creates a new pool with an available hot
spare:

# zpool create tank mirror c0t0d0 c0t1d0 spare c0t2d0

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:

# zpool replace tank c0t0d0 c0t3d0

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:

# zpool remove tank c0t2d0

Example 12 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:

# zpool create pool mirror c0d0 c1d0 mirror c2d0 c3d0 log mirror \
c4d0 c5d0

Example 13 Adding Cache Devices to a ZFS Pool
The following command adds two disks for use as cache devices to a
ZFS storage pool:

# zpool add pool cache c2d0 c3d0

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 iostat option as follows:

# zpool iostat -v pool 5

Example 14 Removing a Mirrored top-level (Log or Data) Device
The following commands remove the mirrored log device mirror-2 and
mirrored top-level data device mirror-1.

Given this configuration:

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

The command to remove the mirrored log mirror-2 is:

# zpool remove tank mirror-2

The command to remove the mirrored data mirror-1 is:

# zpool remove tank mirror-1

Example 15 Displaying expanded space on a device
The following command displays the detailed information for the
pool 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.

# 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 - - - - -

INTERFACE STABILITY


Evolving

SEE ALSO


zfs(1M), attributes(5), zpool-features(5)

illumos April 27, 2018 illumos