ZPOOL(1M)ZPOOL(1M)NAMEzpool - configures ZFS storage pools
SYNOPSISzpool [-?]
zpool add [-fn] pool vdev ...
zpool attach [-f] pool device new_device
zpool clear pool [device]
zpool create [-fnd] [-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 [-Hp] [-o field[,...]] "all" | property[,...] pool ...
zpool history [-il] [pool] ...
zpool import [-d dir] [-D]
zpool import [-o mntopts] [-o property=value] ... [-d dir | -c cachefile]
[-D] [-f] [-m] [-N] [-R root] [-F [-n]] -a
zpool import [-o mntopts] [-o property=value] ... [-d dir | -c cachefile]
[-D] [-f] [-m] [-R root] [-F [-n]] pool |id [newpool]
zpool iostat [-T u | d ] [-v] [pool] ... [interval[count]]
zpool list [-T u | d ] [-Hpv] [-o property[,...]] [pool] ... [interval[count]]
zpool offline [-t] pool device ...
zpool online pool device ...
zpool reguid pool
zpool reopen pool
zpool remove pool device ...
zpool replace [-f] pool device [new_device]
zpool scrub [-s] pool ...
zpool set property=value pool
zpool status [-xvD] [-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 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
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 experimen‐
tal 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 can‐
not be 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 dis‐
tinguish where a group ends and another begins. For example, the fol‐
lowing 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 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 three states: online,
degraded, or faulted. An online pool has all devices operating nor‐
mally. 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 follow‐
ing states:
DEGRADED
One or more top-level vdevs is in the degraded state
because one or more component devices are offline. Suffi‐
cient replicas exist to continue functioning.
One or more component devices is in the degraded or faulted
state, but sufficient replicas exist to continue function‐
ing. The underlying conditions are as follows:
o The number of checksum errors exceeds acceptable
levels and the device is degraded as an indica‐
tion that something may be wrong. ZFS continues
to use the device as necessary.
o The number of I/O errors exceeds acceptable lev‐
els. The device could not be marked as faulted
because there are insufficient replicas to con‐
tinue 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 lev‐
els and the device is faulted to prevent further
use of the device.
OFFLINE
The device was explicitly taken offline by the "zpool off‐
line" command.
ONLINE
The device is online and functioning.
REMOVED
The device was physically removed while the system was run‐
ning. 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 identi‐
fied 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 detec‐
tion 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() 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 improve‐
ment 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.
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:
available
Amount of storage available within the pool. This
property can also be referred to by its shortened
column name, "avail".
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 (i.e. zpool online -e). This
space occurs when a LUN is dynamically expanded.
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 asyn‐
chronously. freeing is the amount of space remain‐
ing to be reclaimed. Over time freeing will
decrease while free increases.
health
The current health of the pool. Health can be
"ONLINE", "DEGRADED", "FAULTED", " OFFLINE",
"REMOVED", or "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.
used
Amount of storage space used within the pool.
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 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 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 col‐
umn 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" cre‐
ates 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 set‐
ting is 0 which causes no ditto copies to be created for dedupli‐
cated blocks. The miniumum 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 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 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.
listsnaps=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".
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 fea‐
ture flags is 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 over‐
ridden in this manner.
-n
Displays the configuration that would be used without actu‐
ally 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 zpool. 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 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 [-fnd] [-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" 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 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.
By default all supported features are enabled on the new pool
unless the -d option is specified.
-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 device sharing.
-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.
-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 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,altroot=root"
-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).
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. 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 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" com‐
mand.
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[,...]] "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
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.
-p
Display numbers in parsable (exact) values.
-o field
A comma-separated list of columns to display. name,prop‐
erty,value,source is the default value.
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
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 dir | -c cachefile] [-D]
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 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 dir. The -d option
can be specified multiple times.
-D
Lists destroyed pools only.
zpool import [-o mntopts] [ -o property=value] ... [-d dir | -c
cachefile] [-D] [-f] [-m] [-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. Destroyed pools, pools that were
previously destroyed with the "zpool destroy" command, will not be
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 proper‐
ties 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 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 irretriev‐
ably 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 there is a miss‐
ing log device. Recent transactions can be
lost because the log device will be discarded.
-R root
Sets the "cachefile" property to "none" and
the "altroot" property to "root".
-N
Import the pool without mounting any file sys‐
tems.
-n
Used with the -F recovery option. Determines
whether a non-importable pool can be made
importable again, but does not actually per‐
form the pool recovery. For more details about
pool recovery mode, see the -F option, above.
zpool import [-o mntopts] [ -o property=value] ... [-d dir | -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 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.
-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 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 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" prop‐
erty to "root".
-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 there is a missing log device.
Recent transactions can be lost because the log device will be
discarded.
zpool iostat [-T u | d] [-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 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 indi‐
vidual vdevs within the pool, in addition to the pool-
wide statistics.
zpool list [-T u | d] [-Hvp] [-o props[,...]] [pool] ... [inter‐
val[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 sec‐
onds until Ctrl-C is pressed. 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).
-H
Scripted mode. Do not display headers, and separate
fields by a single tab instead of arbitrary space.
-p
Display numbers in parsable (exact) values.
-o props
Comma-separated list of properties to display. See the
"Properties" section for a list of valid properties.
The default list is "name, size, used, available,
expandsize, capacity, dedupratio, health, altroot"
-v
Verbose statistics. Reports usage statistics for indi‐
vidual vdevs within the pool, in addition to the pool-
wise statistics.
-p Display numbers in parseable (exact) values.
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 reguid pool
Generates a new unique identifier for the pool. You must ensure
that all devices in this pool are online and healthy before per‐
forming this action.
zpool reopen pool
Reopen all the vdevs associated with 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.
-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
only allows one at a time. If a scrub is already in progress, the
"zpool scrub" command terminates it and starts a new scrub. If a
resilver is in progress, ZFS does not allow a scrub to be started
until the resilver 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 status [-xvD] [-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 dis‐
played. 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.
-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.
-v
Displays verbose data error information, printing out a com‐
plete list of all data errors since the last complete pool
scrub.
-D
Display a histogram of deduplication statistics, showing the
allocated (physically present on disk) and referenced (logi‐
cally referenced in the pool) block counts and sizes by ref‐
erence 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).
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 sup‐
ported 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 compat‐
ibility 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 ver‐
sion number.
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 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 pur‐
poses.
# 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 EXPANDSZ CAP DEDUP HEALTH ALTROOT
rpool 19.9G 8.43G 11.4G - 42% 1.00x ONLINE -
tank 61.5G 20.0G 41.5G - 32% 1.00x ONLINE -
zion - - - - - - FAULTED -
Example 7 Destroying a ZFS Storage Pool
The following command destroys the pool "tank" and any datasets con‐
tained 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 should another device fails. 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 Log Device
The following command removes the mirrored log device mirror-2.
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
Example 15 Displaying expanded space on a device
The following command dipslays the detailed information for the data
pool. This pool is comprised of a single raidz vdev where one of its
devices increased its capacity by 1GB. In this example, the pool will
not be able to utilized this extra capacity until all the devices under
the raidz vdev have been expanded.
# zpool list -v data
NAME SIZE ALLOC FREE EXPANDSZ CAP DEDUP HEALTH ALTROOT
data 17.9G 174K 17.9G - 0% 1.00x ONLINE -
raidz1 17.9G 174K 17.9G -
c4t2d0 - - - 1G
c4t3d0 - - - -
c4t4d0 - - - -
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 │
├────────────────────┼─────────────────┤
│Interface Stability │ Evolving │
└────────────────────┴─────────────────┘
SEE ALSOzfs(1M), zpool-features(5), attributes(5)
Mar 6, 2014 ZPOOL(1M)
