zpool(1M) System Administration Commands zpool(1M)NAMEzpool - configures ZFS storage pools
SYNOPSISzpool [-?]
zpool help subcommand | help property property
zpool add [-fn] pool vdev ...
zpool attach [-f] pool device new_device
zpool clear [-F [-n]] pool [device]
zpool create [-fn] [-o property=value] ... [-O file-system-property=value]
... [-m mountpoint] [-R root] pool vdev ...
zpool destroy [-f] pool
zpool detach pool device
zpool export [-f] pool ...
zpool get all | property[,...] pool ...
zpool history [-il] [pool] ...
zpool import [-d path ...] [-D]
zpool import [-d path ...] -c cachefile] [-F [-n]] <pool | id>
zpool import [-o mntopts] [-o property=value] ... [-d path ... |
-c cachefile] [-D] [-f] [-m] [-N] [-R root] [-F [-n]] -a
zpool import [-o mntopts] [-o property=value] ... [-d path ... |
-c cachefile] [-D] [-f] [-m] [-R root] [-F [-n]] pool | id [newpool]
zpool iostat [-T d|u ] [-v] [pool] ... [interval[count]]
zpool list [-H] [-o property[,...]] [-T d|u ] [pool] ... [interval[count]]
zpool offline [-t] pool device ...
zpool online [-e] pool device ...
zpool remove pool device ...
zpool replace [-f] pool device [new_device]
zpool scrub [-s] pool ...
zpool set property=value pool
zpool split [-R altroot] [-n] [-o mntopts] [-o property=value] pool
newpool [device ...]
zpool status [-xv] [-T d|u ] [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 replica‐
tion 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 indi‐
vidual slices or partitions, though the recommended mode of opera‐
tion 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. When given a whole disk, ZFS auto‐
matically 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 speci‐
fies 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 speci‐
fied, 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 combina‐
tions) are not allowed.
A pool can have any number of virtual devices at the top of the config‐
uration (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, sepa‐
rated by whitespace. The keywords mirror and raidz are used to distin‐
guish 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
Pool or 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 automat‐
ically 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 four states:
ONLINE
A pool that has all devices operating normally.
DEGRADED
A pool with one or more failed devices, but the data is still
available due to a redundant configuration.
FAULTED
A pool with corrupted metadata, or one or more faulted devices, and
insufficient replicas to continue functioning.
SUSPENDED
A pool that is waiting for device connectivity to be restored. A
suspended pool remains in the wait state until the device issue is
resolved.
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 follow‐
ing 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 underly‐
ing conditions are as follows:
o The number of checksum errors exceeds acceptable levels
and the device is degraded as an indication that some‐
thing 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 insuffi‐
cient replicas exist to continue functioning. The underlying condi‐
tions 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 com‐
mand.
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 sup‐
ported 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 reattached 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 sparevdev with any number of devices. For
example,
# zpool create pool mirror c0d0 c1d0 spare c2d0 c3d0
Spares 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 the original failed device is physically replaced, brought back
online, or the errors are cleared, either through an FMA event or by
using the zpool online command or zpool clear command, and the state of
the original device becomes healthy, the INUSE spare device will become
AVAIL again.
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() 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 log devices can be
removed by specifying the top-level mirror for the log.
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 num‐
ber 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.
Processes
Each imported pool has an associated process, named zpool-poolname. The
threads in this process are the pool's I/O processing threads, which
handle the compression, checksumming, and other tasks for all I/O asso‐
ciated with the pool. This process exists to provides visibility into
the CPU utilization of the system's storage pools. The existence of
this process is an unstable interface.
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 within the pool that has been physically
allocated. This property can also be referred to by its shortened
column name, alloc.
capacity
Percentage of pool space used. This property can also be referred
to by its shortened column name, cap.
free
Number of blocks within the pool that are not allocated.
guid
A unique identifier for the pool.
health
The current health of the pool. Health can be ONLINE, DEGRADED, or
FAULTED, or SUSPENDED.
size
Total size of the storage pool.
These 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 character‐
istics 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 at import time:
readonly=on | off
Controls whether the pool can be modified. When enabled, any syn‐
chronous data that exists only in the intent log is not accessible
until the pool is imported in read-write mode.
Importing a pool in read-only mode has the following limitations:
o Attempts to set additional pool properties during the
import are ignored.
o All file system mounts are converted to include the
read-only (ro) mount option.
A pool that has been imported in read-only mode can be restored to
read-write mode by exporting and importing the pool.
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 a larger device is added or
attached to the pool or when a larger device replaces a smaller
device in the pool. If set to on, the pool will be resized accord‐
ing 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 col‐
umn 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.
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 connec‐
tivity to the underlying storage device(s) or a failure of all
devices within the pool. The behavior of such an event is deter‐
mined as follows:
wait
Blocks all I/O access to the pool until the device connectivity
is recovered and the errors are cleared. A pool remains in the
wait state until the device issue is resolved. 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.
listsnaps=on | off
Controls whether snapshot information associated with this pool is
displayed when zfs listis run without the -t option. The default
value is on.
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 spe‐
cific version is needed for backwards compatibility. This property
can be any number between 1 and the current version reported by
zpool upgrade -v.
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 help subcommand | help property property
Displays zpool subcommand usage information. You can display help
for a specific subcommand or property. If you display help for a
specific subcommand or property, the command syntax or property
value is displayed. Using zpool help without any arguments displays
a complete list of zpool subcommands.
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 overrid‐
den 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.
Do not add a disk that is currently configured as a quorum device
to a ZFS storage pool. After a disk is in the pool, that disk can
then be configured as a quorum device.
zpool attach [-f] pool device new_device
Attaches new_device to an existing zpool 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 clear [-F [-n]] 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.
-F
Initiates recovery mode for an unopenable pool. Attempts to
discard the last few transactions in the pool to return it to
an openable state. Not all damaged pools can be recovered by
using this option. If successful, the data from the discarded
transactions is irretrievably lost.
-n
Used in combination with the -F flag. Check whether discarding
transactions would make the pool openable, but do not actually
discard any transactions.
zpool create [-fn] [-o property=value] ... [-O file-system-prop‐
erty=value] ... [-m mountpoint] [-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" sec‐
tion.
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 overrid‐
den 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.
-f
Forces use of vdevs, even if they appear in use or specify a
conflicting replication level. Not all devices can be overrid‐
den in this manner.
-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 if a device is currently in use.
-o property=value [-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
[-O file-system-property=value] ...
Sets the specified properties for the pool's top-level file
system. See the "Properties" section of zfs(1M) for a list of
valid properties that can be set.
-R root
Equivalent to -o cachefile=none,altroot=root
-m mountpoint
Sets the mount point for the pool's top-level file system. 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).
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 endi‐
anness) and imported as long as a sufficient number of devices are
present.
Before exporting the pool, all datasets within the pool are
unmounted.
For pools to be portable, you must give the zpool command whole
disks, not just slices, so that ZFS can label the disks with porta‐
ble 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.
zpool get all | property[,...] pool ...
Retrieves the given list of properties (or all properties if all is
used) for the specified storage pool(s). These properties are dis‐
played 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.
zpool history [-il] [pool] ...
Displays the command history of the specified pools or all pools if
no pool is specified.
-i
Displays internally logged ZFS events in addition to user ini‐
tiated events.
-l
Displays log records in long format, which in addition to stan‐
dard format includes, the user name, the hostname, and the zone
in which the operation was performed.
zpool import [-d path ... ] [-D]
zpool import [-d path ... | -c cachefile] [-F [-n]]pool | id
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 and device paths 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. Pools that were pre‐
viously 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 avail‐
able.
-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 path, where path can be a
directory or a device path. The -d option can be specified mul‐
tiple times.
-D
Lists destroyed pools only.
zpool import [-o mntopts] [ -o property=value] ... [-d path ... | -c
cachefile] [-D] [-f] [-m] [-N] [-R root] [-F [-n]] -a
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. Pools that were previously
destroyed with the zpool destroy command, are not imported unless
the -D option is specified.
-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.
-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 path
Searches for devices or files in path. 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 transac‐
tions. 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.
-a
Searches for and imports all pools found.
-m
Allows a pool to import when a log device is missing.
-R root
Sets the cachefile property to none and the altroot property to
root.
-N
Imports the pool without mounting any file systems.
-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.
zpool import [-o mntopts] [ -o property=value] ... [-d path ... | -c
cachefile] [-D] [-f] [-m] [-R root] [-F [-n]] 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 persistent name newpool. Otherwise, it is
imported with the same name as its exported name. Do not import a
root pool with a new name. Otherwise, the system might not boot.
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.
-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.
-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 path
Searches for devices or files in path. 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. Attempts to return the
pool to an importable state by discarding the last few transac‐
tions. 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.
-R root
Sets the cachefile property to none and the altroot property to
root.
-N
Imports the pool without mounting any file systems.
-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.
-m
Allows a pool to import when a log device is missing.
zpool iostat [-T d|u] [-v] [pool] ... [interval[count]]
Displays I/O statistics for the given pools. When given an inter‐
val, the statistics are printed every interval seconds until Ctrl-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 d|u
Display a time stamp.
Specify d for standard date format. See date(1). Specify u for
a printed representation of the internal representation of
time. See time(2).
-v
Verbose statistics. Reports usage statistics for individual
vdevs within the pool, in addition to the pool-wide statistics.
zpool list [-H] [-o props[,...]] [-T d|u] [pool] ...
Lists the given pools along with a health status and space usage.
When given no arguments, all pools in the system are listed.
When given an interval, the status and space usage are displayed
every interval seconds until Ctrl-C is entered. If count is speci‐
fied, the command exits after count reports are displayed.
-H
Scripted mode. Do not display headers, and separate fields by a
single tab instead of arbitrary space.
-o props
Comma-separated list of properties to display. See the "Proper‐
ties" section for a list of valid properties. The default list
is name, size, allocated, free, capacity, health, altroot.
-T d|u
Display a time stamp.
Specify d for standard date format. See date(1). Specify u for
a printed representation of the internal representation of
time. See time(2).
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 or cache devices.
-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 or cache devices.
-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 remove pool device ...
Removes the specified device from the pool. This command currently
only supports removing hot spares, cache, and log devices. A mir‐
rored log device can be removed by specifying the top-level mirror
for the log. Non-log devices that are part of a mirrored configura‐
tion can be removed using the zpool detach command. Non-redundant
and raidz devices cannot be removed from a pool.
zpool replace [-f] pool old_device [new_device]
Replaces old_device with new_device. This is equivalent to attach‐
ing 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 replace‐
ment is useful after an existing disk has failed and has been phys‐
ically replaced. In this case, the new disk may have the same
/dev/dsk path as the old device, even though it is actually a dif‐
ferent disk. ZFS recognizes this.
In zpool status output, the old_device is shown under the word
replacing with the string /old appended to it. Once the resilver
completes, both the replacing and the old_device are automatically
removed. If the new device fails before the resilver completes and
a third device is installed in its place, then both failed devices
will show up with /old appended, and the resilver starts over
again. After the resilver completes, both /old devices are removed
along with the word replacing.
-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] pool ...
Begins a 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 comple‐
tion.
Scrubbing and resilvering are very similar operations. The differ‐
ence 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 fail‐
ure.
Because scrubbing and resilvering are I/O-intensive operations, ZFS
allows only one at a time. If a scrub is already in progress, a
subsequent zpool scrub returns an error, with the advice to use
zpool scrub -s to cancel the current scrub. If a resilver is in
progress, ZFS does not allow a scrub to be started until the resil‐
ver completes.
-s
Stop scrubbing.
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 [-R altroot] [-n] [-o mntopts] [-o property=value] pool
newpool [device ...]
Splits off one disk from each mirrored top-level vdev in a pool and
creates a new pool from the split-off disks. The original pool must
be made up of one or more mirrors and must not be in the process of
resilvering. The split subcommand chooses the last device in each
mirror vdev unless overridden by a device specification on the com‐
mand line.
When using a device argument, split includes the specified
device(s) in a new pool and, should any devices remain unspecified,
assigns the last device in each mirror vdev to that pool, as it
does normally. If you are uncertain about the outcome of a split
command, use the -n ("dry-run") option to ensure your command will
have the effect you intend.
-R altroot
Automatically import the newly created pool after splitting,
using the specified altroot parameter for the new pool's alter‐
nate root. See the altroot description in the "Properties" sec‐
tion, above.
-n
Displays the configuration that would be created without actu‐
ally splitting the pool. The actual pool split could still fail
due to insufficient privileges or device status.
-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. Valid only in conjunction
with the -R option.
-o property=value
Sets the specified property on the new pool. See the "Proper‐
ties" section, above, for more information on the available
pool properties.
zpool status [-xv] [-T d|u] [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 dis‐
played. For more information on pool and device health, see the
"Device Failure and Recovery" section.
When given an interval, the status and space usage are displayed
every interval seconds until Ctrl-C is entered. If count is speci‐
fied, the command exits after count reports are displayed.
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.
-x
Only display status for pools that are exhibiting errors or are
otherwise unavailable.
-v
Displays verbose data error information, printing out a com‐
plete list of all data errors since the last complete pool
scrub.
-T d|u
Display a time stamp.
Specify d for standard date format. See date(1). Specify u for
a printed representation of the internal representation of
time. See time(2).
zpool upgrade
Identifies a pool's on-disk version, which determines available
pool features in the currently running software release. You can
continue to use older pool versions, but some features might not be
available. A pool can be upgraded by using the zpool upgrade -a
command. You will not be able to access a pool of a later version
on a system that runs an earlier software version.
zpool upgrade -v
Displays ZFS pool versions supported by the current software. The
current ZFS pool versions and all previous supported versions are
displayed, along with an explanation of the features provided with
each version.
zpool upgrade [-V version] -a | pool ...
Upgrades the specified pool to the latest on-disk version. If this
command reveals that a pool is out-of-date, the pool can subse‐
quently be upgraded using the zpool upgrade -a command. A pool that
is upgraded will not be accessible on a system that runs an earlier
software release.
-a
Upgrades all pools.
-V version
Upgrade to the specified version, which must be higher than the
current version. If the -V flag is not specified, the pool is
upgraded to the most recent version.
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 mir‐
ror contains two disks.
# zpool create tank mirror c0t0d0 c0t1d0 mirror c0t2d0 c0t3d0
Example 3 Adding a Mirror to a ZFS Storage Pool
The following command adds two mirrored disks to the pool tank, assum‐
ing 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 4 Listing Available ZFS Storage Pools
The following command lists all available pools on the system.
# zpool list
NAME SIZE ALLOC FREE CAP HEALTH ALTROOT
pool 136G 109M 136G 0% ONLINE -
rpool 67.5G 12.6G 54.9G 18% ONLINE -
Example 5 Listing All Properties for a Pool
The following command lists all the properties for a pool.
% zpool get all pool
NAME PROPERTY VALUE SOURCE
pool size 68G -
pool capacity 0% -
pool altroot - default
pool health ONLINE -
pool guid 17810032335006077463 default
pool version 29 default
pool bootfs - default
pool delegation on default
pool autoreplace off default
pool cachefile - default
pool failmode wait default
pool listsnapshots on default
pool autoexpand off default
pool free 68.0G -
pool allocated 130K -
pool readonly off -
Example 6 Destroying a ZFS Storage Pool
The following command destroys the pool tank and any datasets contained
within.
# zpool destroy -f tank
Example 7 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 8 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: 7678868315469843843
state: ONLINE
action: The pool can be imported using its name or numeric identifier.
config:
tank ONLINE
mirror-0 ONLINE
c1t2d0 ONLINE
c1t3d0 ONLINE
# zpool import tank
Example 9 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 pool version 29.
All pools are formatted using this version.
Example 10 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
After the device has been resilvered, the spare is automatically
detached and is made available should another device fail. The hot
spare can be permanently removed from the pool using the following com‐
mand:
# zpool remove tank c0t2d0
Example 11 Creating a ZFS Pool with Separate Mirrored Log Devices
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 12 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 13 Removing a Mirrored Log Device
The following example shows how to remove the mirrored log device mir‐
ror-2 in the pool tank.
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
# zpool remove tank mirror-2
Example 14 Recovering a Faulted ZFS Pool
If a pool is faulted but recoverable, a message indicating this state
is provided by zpool status if the pool was cached (see cachefile
above), or as part of the error output from a failed zpool import of
the pool.
Recover a cached pool with the zpool clear command:
# zpool clear -F data
Pool data returned to its state as of Thu Jun 07 10:50:35 2012.
Discarded approximately 29 seconds of transactions.
If the pool configuration was not cached, use zpool import with the
recovery mode flag:
# zpool import -F data
Pool data returned to its state as of Thu Jun 07 10:50:35 2012.
Discarded approximately 29 seconds of transactions.
Example 15 Importing a ZFS Pool with a Missing Log Device
The following examples illustrate attempts to import a pool with a
missing log device. The -m option is used to complete the import opera‐
tion.
Additional devices are known to be part of this pool, though their
exact configuration cannot be determined.
# zpool import tank
The devices below are missing, use -m to import the pool anyway:
c5t0d0 [log]
cannot import 'tank': one or more devices is currently unavailable
# zpool import -m tank
# zpool status tank
pool: tank
state: DEGRADED
status: One or more devices could not be opened. Sufficient replicas
exist for
the pool to continue functioning in a degraded state.
action: Attach the missing device and online it using 'zpool online'.
see: http://www.sun.com/msg/ZFS-8000-2Q
scan: none requested
config:
NAME STATE READ WRITE CKSUM
tank DEGRADED 0 0 0
c7t0d0 ONLINE 0 0 0
logs
1693927398582730352 UNAVAIL 0 0 0 was
/dev/dsk/c5t0d0
errors: No known data errors
The following example shows how to import a pool with a missing mir‐
rored log device.
# zpool import tank
The devices below are missing, use ?-m? to import the pool anyway:
mirror-1 [log]
c5t0d0
c5t1d0
# zpool import -m tank
# zpool status tank
pool: tank
state: DEGRADED
status: One or more devices could not be opened. Sufficient replicas
exist for the pool to continue functioning in a degraded state.
action: Attach the missing device and online it using 'zpool online'.
see: http://www.sun.com/msg/ZFS-8000-2Q
scan: none requested
config:
NAME STATE READ WRITE CKSUM
tank DEGRADED 0 0 0
c7t0d0 ONLINE 0 0 0
logs
mirror-1 UNAVAIL 0 0 0
insufficient replicas
46385995713041169 UNAVAIL 0 0 0 was
/dev/dsk/c5t0d0
13821442324672734438 UNAVAIL 0 0 0 was
/dev/dsk/c5t1d0
errors: No known data errors
Example 16 Importing a Pool By a Specific Path
The following command imports the pool tank by identifying the pool's
specific device paths, /dev/dsk/c9t9d9 and /dev/dsk/c9t9d8, in this
example.
# zpool import -d /dev/dsk/c9t9d9s0 /dev/dsk/c9t9d8s0 tank
An existing limitation is that even though this pool is comprised of
whole disks, the command must include the specific device's slice iden‐
tifier.
EXIT STATUS
The following exit values are returned:
0
Successful completion.
1
An error occurred.
2
Invalid command line options were specified.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │system/file-system/zfs │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOzfs(1M), attributes(5)SunOS 5.10 27 Jul 2012 zpool(1M)
