Updated: 2022/Sep/29
Please read Privacy Policy. It's for your privacy.
ZPOOL(8) System Manager's Manual ZPOOL(8)
NAME
zpool - configures ZFS storage pools
SYNOPSIS
zpool [-?]
zpool add [-fn] pool vdev ...
zpool attach [-f] pool device new_device
zpool clear [-F [-n]] 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 | -c cachefile] [-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] [-N] [-R root] [-F [-n]] pool | id [newpool]
zpool iostat [-T d|u] [-v] [pool] ...
zpool labelclear [-f] device
zpool list [-Hpv] [-o property[,...]] [-T d|u] [pool] ...
[inverval [count]]
zpool offline [-t] pool device ...
zpool online [-e] pool device ...
zpool reguid pool
zpool remove pool device ...
zpool reopen pool
zpool replace [-f] pool device [new_device]
zpool scrub [-s] pool ...
zpool set property=value pool
zpool split [-n] [-R altroot] [-o mntopts] [-o property=value]
pool newpool [device ...]
zpool status [-vx] [-T d|u] [pool] ... [interval [count]]
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(8) for
information on managing datasets.
Virtual Devices (vdevs)
A "virtual device" (vdev) 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. 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 to the device or the geom(4) provider name. 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 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 (or 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 da0 da1 mirror da2 da3
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:
⊕ 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.
⊕ 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:
⊕ The device could be opened, but the contents did not
match expected values.
⊕ 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 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 "spare" vdev with any number of devices. For
example,
# zpool create pool mirror da0 da1 spare da2 da3
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.
This feature requires a userland helper.
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(2) 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 da0 da1 log da2
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, 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
number of devices. For example:
# zpool create pool da0 da1 cache da2 da3
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:
alloc Amount of storage space within the pool that has been
physically allocated.
capacity Percentage of pool space used. This property can also be
referred to by its shortened column name, "cap".
comment 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.
dedupratio The deduplication ratio specified for a pool, expressed as a
multiplier. For example, a dedupratio value of 1.76
indicates that 1.76 units of data were stored but only 1 unit
of disk space was actually consumed. See zfs(8) for a
description of the deduplication feature.
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.
fragmentation
The amount of fragmentation in the pool.
free Number of blocks within the pool that are not allocated.
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.
guid A unique identifier for the pool.
health The current health of the pool. Health can be "ONLINE",
"DEGRADED", "FAULTED", "OFFLINE", "REMOVED", or "UNAVAIL".
size Total size of the storage pool.
unsupported@feature_guid
Information about unsupported features that are enabled on
the pool. See zpool-features(7) 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 characteristics of the
data being written. In addition, ZFS reserves some space for internal
accounting that the zfs(8) command takes into account, but the zpool(8)
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 only be set at import time:
readonly=on | off
If set to on, pool will be imported in read-only mode with the
following restrictions:
⊕ Synchronous data in the intent log will not be accessible
⊕ Properties of the pool can not be changed
⊕ Datasets of this pool can only be mounted read-only
⊕ To write to a read-only pool, a export and import of the pool
is required.
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.
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. Default setting is
0 which causes no ditto copies to be created for deduplicated 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(8) 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(7) 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 feature
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 vdev, 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.
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 [-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 [-fnd] [-o property=value] ... [-O
file-system-property=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 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.
-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 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(7) 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 zfs(8) Properties 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(8).
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[,...]] 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,property,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". 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 [-o mntopts] [-o property=value] ... [-d dir | -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. 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(8) 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 pools only. The -f option is also required.
-f Forces import, even if the pool appears to be potentially
active.
-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 Import the pool without mounting any file systems.
-R root
Sets the "cachefile" property to "none" and the "altroot"
property to "root"
-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.
-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.
-a Searches for and imports all pools found.
zpool import [-o mntopts] [-o property=value] ... [-d dir | -c cachefile]
[-D] [-f] [-m] [-N] [-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(8) 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 pools only. The -f option is also required.
-f Forces import, even if the pool appears to be potentially
active.
-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 Import the pool without mounting any file systems.
-R root
Equivalent to "-o cachefile=none,altroot=root"
-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.
-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 iostat [-T d|u] [-v] [pool] ... [interval [count]]
Displays I/O statistics for the given pools. When given an interval,
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 Print a timestamp.
Use modifier d for standard date format. See date(1). Use
modifier u for unixtime (equals "date +%s").
-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[,...]] [-T d|u] [pool] ... [inverval
[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 output is printed every interval seconds
until Ctrl-C is pressed. If count is specified, the command exits
after count reports are printed.
-T d|u Print a timestamp.
Use modifier d for standard date format. See date(1). Use
modifier u for unixtime (equals "date +%s").
-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.
-v Verbose statistics. Reports usage statistics for individual
vdevs within the pool, in addition to the pool-wide
statistics.
-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, used, available, fragmentation,
expandsize, capacity, health, altroot.
-T d|u Print a timestamp.
Use modifier d for standard date format. See date(1). Use
modifier u for unixtime (equals "date +%s").
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.
-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 performing
this action.
zpool remove pool device ...
Removes the specified device from the pool. This command currently
only supports removing hot spares, cache, and log devices. A mirrored
log device can be removed by specifying the top-level mirror for the
log. Non-log devices that are part of a mirrored configuration can be
removed using the "zpool detach" command. Non-redundant and raidz
devices cannot be removed from a pool.
zpool reopen pool
Reopen all the vdevs associated with the pool.
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 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] 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 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 already in progress, the
"zpool scrub" command returns an error. To start a new scrub, you
have to stop the old scrub with the "zpool scrub -s" command first.
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 split [-n] [-R altroot] [-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
command 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
alternate root. See the altroot description in the
"Properties" section, above.
-n Displays the configuration that would be created without
actually 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(8) 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
"Properties" section, above, for more information on the
available pool properties.
zpool status [-vx] [-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
displayed. For more information on pool and device health, see the
"Device Failure and Recovery" section.
When given an interval, the output is printed every interval seconds
until Ctrl-C is pressed. If count is specified, the command exits
after count reports are printed.
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, having non-native block size or
disabled features will not be included.
-v Displays verbose data error information, printing out a
complete list of all data errors since the last complete pool
scrub.
-T d|u Print a timestamp.
Use modifier d for standard date format. See date(1). Use
modifier u for unixtime (equals "date +%s").
zpool upgrade [-v]
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.
-v Displays legacy ZFS versions supported by the current
software. See zpool-features(7) 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(7) 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 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 da0 da1 da2 da3 da4 da5
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 da0 da1 mirror da2 da3
Example 3 Creating a ZFS Storage Pool by Using Partitions
The following command creates an unmirrored pool using two GPT
partitions.
# zpool create tank da0p3 da1p3
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 da2 da3
Example 6 Listing Available ZFS Storage Pools
The following command lists all available pools on the system.
# zpool list
NAME SIZE ALLOC FREE FRAG EXPANDSZ CAP DEDUP HEALTH ALTROOT
pool 2.70T 473G 2.24T 33% - 17% 1.00x ONLINE -
test 1.98G 89.5K 1.98G 48% - 0% 1.00x ONLINE -
Example 7 Listing All Properties for a Pool
The following command lists all the properties for a pool.
# zpool get all pool
pool size 2.70T -
pool capacity 17% -
pool altroot - default
pool health ONLINE -
pool guid 2501120270416322443 default
pool version 28 default
pool bootfs pool/root local
pool delegation on default
pool autoreplace off default
pool cachefile - default
pool failmode wait default
pool listsnapshots off default
pool autoexpand off default
pool dedupditto 0 default
pool dedupratio 1.00x -
pool free 2.24T -
pool allocated 473G -
pool readonly off -
Example 8 Destroying a ZFS Storage Pool
The following command destroys the pool "tank" and any datasets
contained within.
# zpool destroy -f tank
Example 9 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 10 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
da0 ONLINE
da1 ONLINE
Example 11 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 28.
Example 12 Managing Hot Spares
The following command creates a new pool with an available hot spare:
# zpool create tank mirror da0 da1 spare da2
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 da0 da2
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 da2
Example 13 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 da0 da1 mirror da2 da3 log mirror da4 da5
Example 14 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 da2 da3
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 subcommand as follows:
# zpool iostat -v pool 5
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 10GB. 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 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% -
ada0 - - - - -
ada1 - - - - 10G
ada2 - - - - -
Example 16 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
da0 ONLINE 0 0 0
da1 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
da2 ONLINE 0 0 0
da3 ONLINE 0 0 0
logs
mirror-2 ONLINE 0 0 0
da4 ONLINE 0 0 0
da5 ONLINE 0 0 0
The command to remove the mirrored log mirror-2 is:
# zpool remove tank mirror-2
Example 17 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 the -c
cachefile argument 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 Tue Sep 08 13:23:35 2009.
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 Tue Sep 08 13:23:35 2009.
Discarded approximately 29 seconds of transactions.
SEE ALSO
zpool-features(7), zfs(8), zfsd(8)
AUTHORS
This manual page is a mdoc(7) reimplementation of the OpenSolaris manual
page zpool(1M), modified and customized for FreeBSD and licensed under
the Common Development and Distribution License (CDDL).
The mdoc(7) implementation of this manual page was initially written by
Martin Matuska <mm@FreeBSD.org>.
NetBSD 10.99 July 26, 2014 NetBSD 10.99