Manual Pages for UNIX Darwin command on man zfs

zfs(8) BSD System Manager's Manual zfs(8)

NAME

zfs - configures ZFS file systems

SYNOPSIS

zzffss [-??]

zzffss ccrreeaattee [[-oo property=value]]... filesystem

zzffss ccrreeaattee [-ss] [-bb blocksize] [[-oo property=value]]... -VV size volume

zzffss ddeessttrrooyy [-rrRRff] filesystem|volume|snapshot

zzffss ssnnaappsshhoott [-rr] filesystem@name|volume@name

zzffss rroollllbbaacckk [-rrRRff] snapshot

zzffss lliisstt [-rrHH] [-oo prop[,prop] ]... [ -tt type[,type]...]

[ -ss prop [-ss prop]... [ -SS prop [-SS prop]...

zzffss ggeett [-rrHHpp] [-oo field[,field]...]

[-ss source[,source]...] all | property[,property]...

filesystem|volume|snapshot ...

zzffss iinnhheerriitt [-rr] property filesystem|volume... ...

zzffss mmoouunntt

zzffss mmoouunntt [-oo options] [-OO] -aa

zzffss mmoouunntt [-oo options] [-OO] filesystem

zzffss uunnmmoouunntt [-ff] -aa

zzffss uunnmmoouunntt [-ff] filesystem|mountpoint

zzffss sshhaarree -aa

zzffss sshhaarree filesystem

zzffss uunnsshhaarree [-ff] -aa

zzffss uunnsshhaarree [-ff] filesystem|mountpoint

zzffss sseenndd [-ii snapshot1] snapshot2

zzffss rreecceeiivvee [-vvnnFF ] filesystem|volume|snapshot

zzffss rreecceeiivvee [-vvnnFF ] -dd filesystem

DESCRIPTION

The zzffss command configures ZFS datasets within a ZFS storage pool, as described in zzppooooll(8). A dataset is identified by a unique path within the ZFS namespace. For example: pool/{filesystem,volume,snapshot}

hr te aiu lnt o a aae nm i MAXNAMELEN (5 bts.

A dataset can be one of the following: file system A standard POSIX file system. ZFS file systems can be mounted within the standard file system namespace and behave like any other file system. volume A logical volume exported as a raw or block device. This

type of dataset should only be used under special cir-

cumstances. File systems are typically used in most environments.

snapshot A read-only version of a file system or volume at a

given point in time. It is specified as filesystem@name or volume@name.

ZZFFSS RReeaadd-oonnllyy IImmpplleemmeennttaattiioonn

ZFS on OSX is implemented as a readonly filesystem by default. This means that only the ZFS subcommands that do non write operations are permitted. Permitted subcommands are lliisstt, ggeett, mmoouunntt, uunnmmoouunntt, and sseenndd. A full ZFS implementation that allows all subcommands and is read/write is available for download at http://developer.apple.com/. To determine which version of ZFS is loaded(readonly or writable):

## kkeexxttssttaatt || ggrreepp zzffss

com.apple.filesystems.zfs.readonly is the readonly kext version.

com.apple.filesystems.zfs is the writable kext version.

ZZFFSS FFiillee SSyysstteemm HHiieerraarrcchhyy A ZFS storage pool is a logical collection of devices that provide space for datasets. A storage pool is also the root of the ZFS file system hierarchy. The root of the pool can be accessed as a file system, such as mounting and unmounting, taking snapshots, and setting properties. The physical storage characteristics, however, are managed by the zzppooooll(8) command. See zzppooooll(8) for more information on creating and administering pools. SSnnaappsshhoottss

A snapshot is a read-only copy of a file system or volume. Snapshots

can be created extremely quickly, and initially consume no additional space within the pool. As data within the active dataset changes, the snapshot consumes more data than would otherwise be shared with the active dataset. Snapshots can have arbitrary names. Snapshots of volumes can be cloned or rolled back, but cannot be accessed independently.

File system snapshots can be accessed under the ".zfs/snapshot" direc-

tory in the root of the file system. Snapshots are automatically

mounted on demand and may be unmounted at regular intervals. The visi-

bility of the ".zfs" directory can be controlled by the "snapdir" prop-

erty. CClloonneess A clone is a writable volume or file system whose initial contents are the same as another dataset. As with snapshots, creating a clone is nearly instantaneous, and initially consumes no additional space. Clones can only be created from a snapshot. When a snapshot is cloned, it creates an implicit dependency between the parent and child. Even though the clone is created somewhere else in the dataset hierarchy, the original snapshot cannot be destroyed as long as a clone exists. The "origin" property exposes this dependency, and the ddeessttrrooyy command lists any such dependencies, if they exist.

The clone parent-child dependency relationship can be reversed by using

the "pprroommoottee" subcommand. This causes the "origin" file system to become a clone of the specified file system, which makes it possible to destroy the file system that the clone was created from. MMoouunntt PPooiinnttss Creating a ZFS file system is a simple operation, so the number of file systems per system will likely be numerous. To cope with this, ZFS

automatically manages mounting and unmounting file systems. All auto-

matically managed file systems are mounted by ZFS at boot time. By default, file systems are mounted under /Volumes/fs, where fs is the name of the file system in the ZFS namespace. Directories are created and destroyed as needed.

A file system can also have a mount point set in the "mountpoint" prop-

erty. This directory is created as needed, and ZFS automatically mounts

the file system when the "zzffss mmoouunntt -aa" command is invoked. The mount-

point property can be inherited, so if VVoolluummeess//ppooooll//hhoommee has a mount point of //eexxppoorrtt//ssttuuffff, then ppooooll//hhoommee//uusseerr automatically inherits a mount point of //eexxppoorrtt//ssttuuffff//uusseerr. A file system mountpoint property of "none" prevents the file system from being mounted. If needed, ZFS file systems can also be managed with traditional tools (mmoouunntt, uummoouunntt). If a file system's mount point is set to "legacy", ZFS makes no attempt to manage the file system, and the administrator is responsible for mounting and unmounting the file system. NNaattiivvee PPrrooppeerrttiieess Properties are divided into two types, native properties and user defined properties. Native properties either export internal statistics or control ZFS behavior. In addition, native properties are either

editable or read-only. User properties have no effect on ZFS behavior,

but you can use them to annotate datasets in a way that is meaningful in your environment. For more information about user properties, see the "User Properties" section. Every dataset has a set of properties that export statistics about the dataset as well as control various behavior. Properties are inherited from the parent unless overridden by the child. Snapshot properties can

not be edited; they always inherit their inheritable properties. Prop-

erties that are not applicable to snapshots are not displayed. The values of numeric properties can be specified using the following

human-readable suffixes (for example, "k", "KB", "M", "Gb", etc, up to

Z for zettabyte). The following are all valid (and equal) specifica-

tions: "1536M", "1.5g", "1.50GB".

The values of non-numeric properties are case sensitive and must be

lowercase, except for "mountpoint" and "sharenfs".

The first set of properties consist of read-only statistics about the

dataset. These properties cannot be set, nor are they inherited. Native properties apply to all dataset types unless otherwise noted.

ttyyppee The type of dataset: "filesystem", "volume", "snap-

shot", or "clone". ccrreeaattiioonn The time this dataset was created. uusseedd The amount of space consumed by this dataset and all its descendants. This is the value that is checked against this dataset's quota and reservation. The

space used does not include this dataset's reserva-

tion, but does take into account the reservations of any descendant datasets. The amount of space that a dataset consumes from its parent, as well as the amount of space that will be freed if this dataset is recursively destroyed, is the greater of its space used and its reservation.

When snapshots (see the "Snapshots" section) are cre-

ated, their space is initially shared between the

snapshot and the file system, and possibly with previ-

ous snapshots. As the file system changes, space that was previously shared becomes unique to the snapshot,

and counted in the snapshot's space used. Addition-

ally, deleting snapshots can increase the amount of space unique to (and used by) other snapshots. The amount of space used, available, or referenced does not take into account pending changes. Pending

changes are generally accounted for within a few sec-

onds. Committing a change to a disk using ffssyynncc(3c) or OOSSYYNNCC does not necessarily guarantee that the space usage information is updated immediately. aavvaaiillaabbllee The amount of space available to the dataset and all its children, assuming that there is no other activity in the pool. Because space is shared within a pool, availability can be limited by any number of factors, including physical pool size, quotas, reservations, or other datasets within the pool. This property can also be referred to by its shortened column name, "avail". rreeffeerreenncceedd The amount of data that is accessible by this dataset, which may or may not be shared with other datasets in

the pool. When a snapshot or clone is created, it ini-

tially references the same amount of space as the file

system or snapshot it was created from, since its con-

tents are identical. This property can also be referred to by its shortened column name, "refer". ccoommpprreessssrraattiioo The compression ratio achieved for this dataset, expressed as a multiplier. Compression can be turned

on by running "zfs set compression=on dataset". The

default value is "off". mmoouunntteedd For file systems, indicates whether the file system is currently mounted. This property can be either "yes" or "no". oorriiggiinn For cloned file systems or volumes, the snapshot from which the clone was created. The origin cannot be

destroyed (even with the -rr or -ff options) so long as

a clone exists. The following two properties can be set to control the way space is allocated between datasets. These properties are not inherited, but do affect their descendants. qquuoottaa==size | none

Limits the amount of space a dataset and its descendants can con-

sume. This property enforces a hard limit on the amount of space used. This includes all space consumed by descendants, including file systems and snapshots. Setting a quota on a descendant of a dataset that already has a quota does not override the ancestor's quota, but rather imposes an additional limit. Quotas cannot be set on volumes, as the "volsize" property acts as an implicit quota. rreesseerrvvaattiioonn==size | none

The minimum amount of space guaranteed to a dataset and its descen-

dants. When the amount of space used is below this value, the dataset is treated as if it were taking up the amount of space specified by its reservation. Reservations are accounted for in the parent datasets' space used, and count against the parent datasets' quotas and reservations. This property can also be referred to by its shortened column name, "reserv". vvoollssiizzee==size For volumes. ZFS volumes are not supported yet in OSX. vvoollbblloocckkssiizzee==blocksize For volumes. ZFS volumes are not supported yet in OSX. rreeccoorrddssiizzee==size Specifies a suggested block size for files in the file system. This property is designed solely for use with database workloads that

access files in fixed-size records. ZZFFSS automatically tunes block

sizes according to internal algorithms optimized for typical access patterns. For databases that create very large files but access them in small random chunks, these algorithms may be suboptimal. Specifying a

"recordsize" greater than or equal to the record size of the data-

base can result in significant performance gains. Use of this prop-

erty for general purpose file systems is strongly discouraged, and may adversely affect performance. The size specified must be a power of two greater than or equal to 512 and less than or equal to 128 Kbytes. Changing the file system's rreeccoorrddssiizzee only affects files created afterward; existing files are unaffected. This property can also be referred to by its shortened column name, "recsize". mmoouunnttppooiinntt==path | none | legacy Controls the mount point used for this file system. See the "Mount Points" section for more information on how this property is used. When the mountpoint property is changed for a file system, the file system and any children that inherit the mount point are unmounted.

If the new value is "legacy", then they remain unmounted. Other-

wise, they are automatically remounted in the new location if the property was previously "legacy" or "none", or if they were mounted

before the property was changed. In addition, any shared file sys-

tems are unshared and shared in the new location. sshhaarreennffss==on | off | opts Controls whether the file system is shared via NNFFSS, and what options are used. A file system with a sharenfs property of "off" is managed through traditional tools such as sshhaarree(1M),

uunnsshhaarree(1M), and ddffssttaabb(4). Otherwise, the file system is automati-

cally shared and unshared with the "zzffss sshhaarree" and "zzffss uunnsshhaarree" commands. If the property is set to "on", the sshhaarree(1M) command is invoked with no options. Otherwise, the sshhaarree(1M) command is invoked with options equivalent to the contents of this property. When the "sharenfs" property is changed for a dataset, the dataset

and any children inheriting the property are re-shared with the new

options, only if the property was previously "off", or if they were shared before the property was changed. If the new property is "off", the file systems are unshared. cchheecckkssuumm==on | off | fletcher2, | fletcher4 | sha256 Controls the checksum used to verify data integrity. The default value is "on", which automatically selects an appropriate algorithm (currently, fletcher2, but this may change in future releases). The value "off" disables integrity checking on user data. Disabling checksums is NOT a recommended practice.

ccoommpprreessssiioonn==on | off | lzjb | gzip | gzip-N

Controls the compression algorithm used for this dataset. The "lzjb" compression algorithm is optimized for performance while providing decent data compression. Setting compression to "on" uses the "lzjb" compression algorithm. The "gzip" compression algorithm is not yet supported for OSX. The "gzip" compression algorithm uses the same compression as the ggzziipp(1) command. You can specify

the "gzip" level by using the value "gzip-N", where N is an integer

from 1 (fastest) to 9 (best compression ratio). Currently, "gzip"

is equivalent to "gzip-6" (which is also the default for ggzziipp(1)).

This property can also be referred to by its shortened column name "compress". aattiimmee==on | off Controls whether the access time for files is updated when they are read. Turning this property off avoids producing write traffic when reading files and can result in significant performance gains, though it might confuse mailers and other similar utilities. The default value is "on". ddeevviicceess==on | off Controls whether device nodes can be opened on this file system. The default value is "on". eexxeecc==on | off Controls whether processes can be executed from within this file system. The default value is "on". sseettuuiidd==on | off

Controls whether the set-UUIIDD bit is respected for the file system.

The default value is "on". rreeaaddoonnllyy==on | off Controls whether this dataset can be modified. The default value is "off". This property can also be referred to by its shortened column name, "rdonly". ssnnaappddiirr==hidden | visible

Controls whether the ".zfs" directory is hidden or visible in the

root of the file system as discussed in the "Snapshots" section. The default value is "hidden". aaccllmmooddee==ddiissccaarrdd | ggrroouuppmmaasskk | ppaasssstthhrroouugghh Controls how an AACCLL is modified during cchhmmoodd(2). A file system with an "aclmode" property of "ddiissccaarrdd" deletes all AACCLL entries that do not represent the mode of the file. An "aclmode" property of "ggrroouuppmmaasskk" (the default) reduces user or group permissions. The permissions are reduced, such that they are no greater than the group permission bits, unless it is a user entry that has the same UUIIDD as the owner of the file or directory. In this case, the AACCLL

permissions are reduced so that they are no greater than owner per-

mission bits. A file system with an "aclmode" property of "ppaasssstthhrroouugghh" indicates that no changes will be made to the AACCLL other than generating the necessary AACCLL entries to represent the new mode of the file or directory. aacclliinnhheerriitt==ddiissccaarrdd | nnooaallllooww | sseeccuurree | ppaasssstthhrroouugghh Controls how AACCLL entries are inherited when files and directories

are created. A file system with an "aclinherit" property of "ddiiss-

ccaarrdd" does not inherit any AACCLL entries. A file system with an "aclinherit" property value of "nnooaallllooww" only inherits inheritable AACCLL entries that specify "deny" permissions. The property value "sseeccuurree" (the default) removes the "wwrriitteeaaccll" and "wwrriitteeoowwnneerr" permissions when the AACCLL entry is inherited. A file system with an

"aclinherit" property value of "ppaasssstthhrroouugghh" inherits all inherita-

ble AACCLL entries without any modifications made to the AACCLL entries when they are inherited. ccaannmmoouunntt==oonn | ooffff If this property is set to "ooffff", the file system cannot be

mounted, and is ignored by "zzffss mmoouunntt -aa". This is similar to set-

ting the "mountpoint" property to "nnoonnee", except that the dataset still has a normal "mountpoint" property which can be inherited. This allows datasets to be used solely as a mechanism to inherit properties. One use case is to have two logically separate datasets have the same mountpoint, so that the children of both datasets appear in the same directory, but may have different inherited characteristics. The default value is "oonn". This property is not inherited. xxaattttrr==oonn | ooffff

Controls whether extended attributes are enabled for this file sys-

tem. The default value is "oonn". ccooppiieess==11 | 22 | 33 Controls the number of copies of data stored for this dataset. These copies are in addition to any redundancy provided by the

pool, for example, mirroring or raid-z. The copies are stored on

different disks, if possible. The space used by multiple copies is charged to the associated file and dataset, changing the "used" property and counting against quotas and reservations.

Changing this property only affects newly-written data. Therefore,

set this property at file system creation time by using the "-oo

copies=" option. TTeemmppoorraarryy MMoouunntt PPooiinntt PPrrooppeerrttiieess When a file system is mounted, either through mmoouunntt(1M) for legacy mounts or the "zzffss mmoouunntt" command for normal file systems, its mount options are set according to its properties. The correlation between properties and mount options is as follows:

PROPERTY MOUNT OPTION

devices devices/nodevices exec exec/noexec readonly ro/rw setuid setuid/nosetuid xattr xattr/noxattr

In addition, these options can be set on a per-mount basis using the -oo

option, without affecting the property that is stored on disk. The val-

ues specified on the command line override the values stored in the

dataset. The -nnoossuuiidd option is an alias for "nodevices,nosetuid".

These properties are reported as "temporary" by the "zzffss ggeett" command. If the properties are changed while the dataset is mounted, the new setting overrides any temporary settings. UUsseerr PPrrooppeerrttiieess In addition to the standard native properties, ZFS supports arbitrary user properties. User properties have no effect on ZFS behavior, but applications or administrators can use them to annotate datasets.

User property names must contain a colon (":") character, to distin-

guish them from native properties. They might contain lowercase let-

ters, numbers, and the following punctuation characters: colon (":"),

dash ("-"), period ("."), and underscore (""). The expected convention

is that the property name is divided into two portions such as "mod-

ule:property", but this namespace is not enforced by ZZFFSS. User property names can be at most 256 characters, and cannot begin with a dash

("-").

When making programmatic use of user properties, it is strongly sug-

gested to use a reversed DDNNSS domain name for the module component of

property names to reduce the chance that two independently-developed

packages use the same property name for different purposes. Property names beginning with "com.apple." are reserved for use by Apple Inc.

The values of user properties are arbitrary strings, are always inher-

ited, and are never validated. All of the commands that operate on

properties ("zfs list", "zfs get", "zfs set", etc.) can be used to

manipulate both native properties and user properties. Use the "zzffss iinnhheerriitt" command to clear a user property . If the property is not defined in any parent dataset, it is removed entirely. Property values are limited to 1024 characters. VVoolluummeess aass SSwwaapp oorr DDuummpp DDeevviicceess To set up a swap area, create a ZZFFSS volume of a specific size and then

enable swap on that device. For more information, see the EXAMPLES sec-

tion.

Do not swap to a file on a ZZFFSS file system. A ZZFFSS swap file configura-

tion is not supported. Using a ZZFFSS volume as a dump device is not supported. SSUUBBCCOOMMMMAANNDDSS All subcommands that modify state are logged persistently to the pool in their original form. zzffss ?? Displays a help message.

zzffss ccrreeaattee [[-oo property=value]...] filesystem

Creates a new ZZFFSS file system. The file system is automatically mounted according to the "mountpoint" property inherited from the parent.

-oo property=value Sets the specified property as if "zzffss sseett

pprrooppeerrttyy==vvaalluuee" was invoked at the same time the dataset was created. Any editable ZZFFSS property can also be set at creation time.

Multiple -oo options can be specified. An error

results if the same property is specified in

multiple -oo options.

zzffss ccrreeaattee [-ss] [-bb blocksize] [[-oo property=value]...] -VV size volume

Creates a volume of the given size. The size represents the logi-

cal size as exported by the device. By default, a reservation of equal size is created. size is automatically rounded up to the nearest 128 Kbytes to ensure that the volume has an integral number of blocks regardless of blocksize.

-ss Creates a sparse volume with no reservation.

See "volsize" in the Native Properties section for more information about sparse volumes.

-oo property=value Sets the specified property as if "zzffss sseett

pprrooppeerrttyy==vvaalluuee" was invoked at the same time the dataset was created. Any editable ZZFFSS property can also be set at creation time.

Multiple -oo options can be specified. An error

results if the same property is specified in

multiple -oo options.

-bb blocksize Equivalent to "-oo vvoollbblloocckkssiizzee==blocksize". If

this option is specified in conjunction with

"-oo vvoollbblloocckkssiizzee", the resulting behavior is

undefined.

zzffss ddeessttrrooyy [-rrRRff] filesystem|volume|snapshot

Destroys the given dataset. By default, the command unshares any file systems that are currently shared, unmounts any file systems that are currently mounted, and refuses to destroy a dataset that has active dependents (children, snapshots, clones).

-rr Recursively destroy all children. If a snapshot is specified,

destroy all snapshots with this name in descendant file sys-

tems.

-RR Recursively destroy all dependents, including cloned file

systems outside the target hierarchy. If a snapshot is speci-

fied, destroy all snapshots with this name in descendant file systems.

-ff Force an unmount of any file systems using the "uunnmmoouunntt -ff"

command. This option has no effect on non-file systems or

unmounted file systems.

Extreme care should be taken when applying either the -rr or the -ff

options, as they can destroy large portions of a pool and cause unexpected behavior for mounted file systems in use. zzffss cclloonnee snapshot filesystem|volume Creates a clone of the given snapshot. See the "Clones" section for details. The target dataset can be located anywhere in the ZZFFSS hierarchy, and is created as the same type as the original. zzffss pprroommoottee filesystem

Promotes a clone file system to no longer be dependent on its "ori-

gin" snapshot. This makes it possible to destroy the file system

that the clone was created from. The clone parent-child dependency

relationship is reversed, so that the "origin" file system becomes a clone of the specified file system. The snaphot that was cloned, and any snapshots previous to this snapshot, are now owned by the promoted clone. The space they use moves from the "origin" file system to the promoted clone, so enough space must be available to accommodate these snapshots. No new space is consumed by this operation, but the space accounting

is adjusted. The promoted clone must not have any conflicting snap-

shot names of its own. The "rreennaammee" subcommand can be used to rename any conflicting snapshots. zzffss rreennaammee filesystem|volume|snapshot filesystem|volume|snapshot Renames the given dataset. The new target can be located anywhere in the ZZFFSS hierarchy, with the exception of snapshots. Snapshots can only be renamed within the parent file system or volume. When renaming a snapshot, the parent file system of the snapshot does not need to be specified as part of the second argument. Renamed file systems can inherit new mount points, in which case they are unmounted and remounted at the new mount point.

zzffss ssnnaappsshhoott [-rr] filesystem@name|volume@name

Creates a snapshot with the given name. See the "Snapshots" section for details.

-rr Recursively create snapshots of all descendant datasets.

Snapshots are taken atomically, so that all recursive snap-

shots correspond to the same moment in time.

zzffss rroollllbbaacckk [-rrRRff] snapshot

Roll back the given dataset to a previous snapshot. When a dataset is rolled back, all data that has changed since the snapshot is discarded, and the dataset reverts to the state at the time of the

snapshot. By default, the command refuses to roll back to a snap-

shot other than the most recent one. In order to do so, all inter-

mediate snapshots must be destroyed by specifying the -rr option.

The file system is unmounted and remounted, if necessary.

-rr Recursively destroy any snapshots more recent than the one

specified.

-RR Recursively destroy any more recent snapshots, as well as any

clones of those snapshots.

-ff Force an unmount of any file systems using the "uunnmmoouunntt -ff"

command.

zzffss lliisstt [-rrHH] [-oo prop[,prop] ]... [ -tt type[,type]...] [ -ss prop [-ss

prop]... [ -SS prop [-SS prop]... [filesystem|volume|snapshot|/path-

name|./pathname ... Lists the property information for the given datasets in tabular

form. If specified, you can list property information by the abso-

lute pathname or the relative pathname. By default, all datasets are displayed and contain the following fields: name,used,available,referenced,mountpoint

-HH Used for scripting mode. Do not print headers and sepa-

rate fields by a single tab instead of arbitrary white-

space.

-rr Recursively display any children of the dataset on the

command line.

-oo prop A comma-separated list of properties to display. The

property must be one of the properties described in the "Native Properties" section, or the special value "name" to display the dataset name.

-ss prop A property to use for sorting the output by column in

ascending order based on the value of the property. The property must be one of the properties described in the "Properties" section, or the special value "name" to sort by the dataset name. Multiple properties can be

specified at one time using multiple -ss property

options. Multiple -ss options are evaluated from left to

right in decreasing order of importance. The following is a list of sorting criteria: o Numeric types sort in numeric order. o String types sort in alphabetical order. o Types inappropriate for a row sort that row to the literal bottom, regardless of the specified ordering. o If no sorting options are specified the existing behavior of "zzffss lliisstt" is preserved.

-SS prop Same as the -ss option, but sorts by property in descend-

ing order.

-tt type A comma-separated list of types to display, where "type"

is one of "filesystem", "snapshot" or "volume". For

example, specifying "-tt ssnnaappsshhoott" displays only snap-

shots. zzffss sseett property=value filesystem|volume ... Sets the property to the given value for each dataset. Only some properties can be edited. See the "Properties" section for more information on what properties can be set and acceptable values.

Numeric values can be specified as exact values, or in a human-

readable form with a suffix of "B", "K", "M", "G", "T", "P", "E", "Z" (for bytes, Kbytes, Mbytes, gigabytes, terabytes, petabytes, exabytes, or zettabytes, respectively). Properties cannot be set on snapshots.

zzffss ggeett [-rrHHpp] [-oo field[,field]...] [-ss source[,source]...] all |

property[,property]... filesystem|volume|snapshot ... Displays properties for the given datasets. If no datasets are specified, then the command displays properties for all datasets on the system. For each property, the following columns are displayed: name Dataset name property Property name value Property value source Property source. Can either be local, default,

temporary, inherited, or none (-).

All columns are displayed by default, though this can be controlled

by using the -oo option. This command takes a comma-separated list

of properties as described in the "Native Properties" and "User Properties" sections. The special value "all" can be used to display all properties for the given dataset.

-rr Recursively display properties for any children.

-HH Display output in a form more easily parsed by

scripts. Any headers are omitted, and fields are explicitly separated by a single tab instead of an arbitrary amount of space.

-oo field A comma-separated list of columns to display.

"name,property,value,source" is the default value.

-ss source A comma-separated list of sources to display. Those

properties coming from a source other than those in this list are ignored. Each source must be one of the following: "local,default,inherited,temporary,none". The default value is all sources.

-pp Display numbers in parsable (exact) values.

zzffss iinnhheerriitt [-rr] property filesystem|volume ...

Clears the specified property, causing it to be inherited from an ancestor. If no ancestor has the property set, then the default value is used. See the "Properties" section for a listing of default values, and details on which properties can be inherited.

-rr Recursively inherit the given property for all children.

zzffss mmoouunntt Displays all ZZFFSS file systems currently mounted.

zzffss mmoouunntt[-oo opts] [-OO] -aa

Mounts all available ZFS file systems. Invoked automatically as part of the boot process.

-oo opts An optional comma-separated list of mount options to use

temporarily for the duration of the mount. See the "Tem-

porary Mount Point Properties" section for details.

-OO Perform an overlay mount. See mmoouunntt(1M) for more infor-

mation.

zzffss mmoouunntt [-oo opts] [-OO] filesystem

Mounts a specific ZFS file system. This is typically not necessary, as file systems are automatically mounted when they are created or the mountpoint property has changed. See the "Mount Points" section for details.

-oo opts An optional comma-separated list of mount options to use

temporarily for the duration of the mount. See the "Tem-

porary Mount Point Properties" section for details.

-OO Perform an overlay mount. See mmoouunntt(1M) for more infor-

mation.

zzffss uunnmmoouunntt -aa

Unmounts all currently mounted ZZFFSS file systems. Invoked automati-

cally as part of the shutdown process.

zzffss uunnmmoouunntt [-ff] filesystem|mountpoint

Unmounts the given file system. The command can also be given a path to a ZZFFSS file system mount point on the system.

-ff Forcefully unmount the file system, even if it is currently

in use.

zzffss sshhaarree -aa

Share is not supported for ZFS on OSX.

zzffss uunnsshhaarree -aa

Unshare is not supported for ZFS on OSX.

zzffss sseenndd [-ii snapshot1] snapshot2

Creates a stream representation of snapshot2, which is written to standard output. The output can be redirected to a file or to a different system (for example, using sssshh(1). By default, a full stream is generated.

-ii snapshot1 Generate an incremental stream from snapshot1 to

snapshot2. The incremental source snapshot1 can be specified as the last component of the snapshot name (for example, the part after the "@"), and it

is assumed to be from the same file system as snap-

shot2. The format of the stream is evolving. No backwards compatibility is

guaranteed. You may not be able to receive your streams on future ver-

sions of ZZFFSS.

zzffss rreecceeiivvee [-vvnnFF] filesystem|volume|snapshot

zzffss rreecceeiivvee [-vvnnFF] -dd filesystem

Creates a snapshot whose contents are as specified in the stream provided on standard input. If a full stream is received, then a new file system is created as well. Streams are created using the "zzffss sseenndd" subcommand, which by default creates a full stream. "zzffss rreeccvv" can be used as an alias for "zzffss rreecceeiivvee". If an incremental stream is received, then the destination file system must already exist, and its most recent snapshot must match the incremental stream's source. The destination file system and all of its child file systems are unmounted and cannot be accessed during the receive operation. The name of the snapshot (and file system, if a full stream is received) that this subcommand creates depends on the argument type

and the -dd option.

If the argument is a snapshot name, the specified snapshot is cre-

ated. If the argument is a file system or volume name, a snapshot

with the same name as the sent snapshot is created within the spec-

ified filesystem or volume. If the -dd option is specified, the

snapshot name is determined by appending the sent snapshot's name

to the specified filesystem. If the -dd option is specified, any

required file systems within the specified one are created.

-dd Use the name of the sent snapshot to determine the name of

the new snapshot as described in the paragraph above.

-vv Print verbose information about the stream and the time

required to perform the receive operation.

-nn Do not actually receive the stream. This can be useful in

conjunction with the -vv option to determine what name the

receive operation would use.

-FF Force a rollback of the filesystem to the most recent snap-

shot before performing the receive operation. EEXXAAMMPPLLEESS EExxaammppllee 11 Creating a ZFS File System Hierarchy The following commands create a file system named "ppooooll//hhoommee" and a file system named "ppooooll//hhoommee//bboobb". The mount point "//eexxppoorrtt//hhoommee" is set for the parent file system, and automatically inherited by the child file system.

# zfs create pool/home

# zfs set mountpoint=/export/home pool/home

# zfs create pool/home/bob

EExxaammppllee 22 Creating a ZFS Snapshot

The following command creates a snapshot named "yesterday". This snap-

shot is mounted on demand in the ".zfs/snapshot" directory at the root

of the "ppooooll//hhoommee//bboobb" file system.

# zfs snapshot pool/home/bob@yesterday

EExxaammppllee 33 Taking and destroying multiple snapshots The following command creates snapshots named "yyeesstteerrddaayy" of "ppooooll//hhoommee" and all of its descendant file systems. Each snapshot is

mounted on demand in the ".zfs/snapshot" directory at the root of its

file system. The second command destroys the newly created snapshots.

# zzffss ssnnaappsshhoott -rr ppooooll//hhoommee@@yyeesstteerrddaayy

## zzffss ddeessttrrooyy -rr ppooooll//hhoommee@@yyeesstteerrddaayy

EExxaammppllee 44 Turning Off Compression The following commands turn compression off for all file systems under "ppooooll//hhoommee", but explicitly turns it on for "ppooooll//hhoommee//aannnnee".

## zzffss sseett ccoommpprreessssiioonn==ooffff ppooooll//hhoommee

## zzffss sseett ccoommpprreessssiioonn==oonn ppooooll//hhoommee//aannnnee

EExxaammppllee 55 Listing ZFS Datasets The following command lists all active file systems and volumes in the system.

## zzffss lliisstt

NAME USED AVAIL REFER MOUNTPOINT

pool 100G 60G - /Volumes/pool

pool/home 100G 60G - /Volumes/export/home

pool/home/bob 40G 60G 40G /Volumes/export/home/bob

pool/home/bob@yesterday 3M - 40G -

pool/home/anne 60G 60G 40G /Volumes/export/home/anne EExxaammppllee 66 Setting a Quota on a ZFS File System The following command sets a quota of 50 gbytes for "ppooooll//hhoommee//bboobb".

## zzffss sseett qquuoottaa==5500GG ppooooll//hhoommee//bboobb

EExxaammppllee 77 Listing ZFS Properties The following command lists all properties for "ppooooll//hhoommee//bboobb".

## zzffss ggeett aallll ppooooll//hhoommee//bboobb

NAME PROPERTY VALUE SOURCE

pool/home/bob type filesystem -

pool/home/bob creation Fri Feb 23 14:20 2007 -

pool/home/bob used 24.5K -

pool/home/bob available 50.0G -

pool/home/bob referenced 24.5K -

pool/home/bob compressratio 1.00x -

pool/home/bob mounted yes -

pool/home/bob quota 50G local pool/home/bob reservation none default pool/home/bob recordsize 128K default pool/home/bob mountpoint /pool/home/bob default pool/home/bob sharenfs off default pool/home/bob shareiscsi off default pool/home/bob checksum on default pool/home/bob compression off default pool/home/bob atime on default pool/home/bob devices on default pool/home/bob exec on default pool/home/bob setuid on default pool/home/bob readonly off default pool/home/bob zoned off default pool/home/bob snapdir hidden default pool/home/bob aclmode groupmask default pool/home/bob aclinherit secure default pool/home/bob canmount on default pool/home/bob xattr on default The following command gets a single property value.

## zzffss ggeett -HH -oo vvaalluuee ccoommpprreessssiioonn ppooooll//hhoommee//bboobb

on The following command lists all properties with local settings for "ppooooll//hhoommee//bboobb".

## zzffss ggeett -rr -ss llooccaall -oo nnaammee,,pprrooppeerrttyy,,vvaalluuee aallll ppooooll//hhoommee//bboobb

NAME PROPERTY VALUE

pool compression on pool/home checksum off EExxaammppllee 88 Rolling Back a ZFS File System The following command reverts the contents of "ppooooll//hhoommee//aannnnee" to the snapshot named "yyeesstteerrddaayy", deleting all intermediate snapshots.

## zzffss rroollllbbaacckk -rr ppooooll//hhoommee//aannnnee@@yyeesstteerrddaayy

EExxaammppllee 99 Creating a ZFS Clone

The following command creates a writable file system whose initial con-

tents are the same as "ppooooll//hhoommee//bboobb@@yyeesstteerrddaayy".

## zzffss cclloonnee ppooooll//hhoommee//bboobb@@yyeesstteerrddaayy ppooooll//cclloonnee

EExxaammppllee 1100 Promoting a ZFS Clone The following commands illustrate how to test out changes to a file system, and then replace the original file system with the changed one, using clones, clone promotion, and renaming:

## zzffss ccrreeaattee ppooooll//pprroojjeecctt//pprroodduuccttiioonn

populate /pool/project/production with data

## zzffss ssnnaappsshhoott ppooooll//pprroojjeecctt//pprroodduuccttiioonn@@ttooddaayy

## zzffss cclloonnee ppooooll//pprroojjeecctt//pprroodduuccttiioonn@@ttooddaayy ppooooll//pprroojjeecctt//bbeettaa

make changes to /pool/project/beta and test them

## zzffss pprroommoottee ppooooll//pprroojjeecctt//bbeettaa

## zzffss rreennaammee ppooooll//pprroojjeecctt//pprroodduuccttiioonn ppooooll//pprroojjeecctt//lleeggaaccyy

## zzffss rreennaammee ppooooll//pprroojjeecctt//bbeettaa ppooooll//pprroojjeecctt//pprroodduuccttiioonn

once the legacy version is no longer needed, it can be destroyed

## zzffss ddeessttrrooyy ppooooll//pprroojjeecctt//lleeggaaccyy

EExxaammppllee 1111 Inheriting ZFS Properties The following command causes "ppooooll//hhoommee//bboobb" and "ppooooll//hhoommee//aannnnee" to inherit the "checksum" property from their parent.

## zzffss iinnhheerriitt cchheecckkssuumm ppooooll//hhoommee//bboobb ppooooll//hhoommee//aannnnee

EExxaammppllee 1122 Replicating ZFS Data The following commands send a full stream and then an incremental stream to respective backup files, restoring them into "ppoooollBB//rreecceeiivveedd//ffss@a" and "ppoooollBB//rreecceeiivveedd//ffss@@bb", respectively. "ppoooollBB" must contain the file system "ppoooollBB//rreecceeiivveedd", and must not initially contain "ppoooollBB//rreecceeiivveedd//ffss".

# zfs send pool/fs@a > /tmp/backupfull \

# zfs receive poolB/received/fs@a < /tmp/backupfull

# zfs send -i a pool/fs@b > /tmp/backup.today \

# zfs receive poolB/received/fs < /tmp/backup.today

EExxaammppllee 1133 Using the zfs receive -d Option

The following command sends a full stream of "ppoooollAA//ffssAA//ffssBB@@ssnnaapp" to a backup file, receiving it into "ppoooollBB//rreecceeiivveedd//ffssAA//ffssBB@@ssnnaapp". The "ffssAA//ffssBB@@ssnnaapp" portion of the received snapshot's name is determined

from the name of the sent snapshot. "ppoooollBB" must contain the file sys-

tem "ppoooollBB//rreecceeiivveedd". If "ppoooollBB//rreecceeiivveedd//ffssAA" does not exist, it will be created as an empty file system.

## zzffss sseenndd ppoooollAA//ffssAA//ffssBB@@ssnnaapp >> //ttmmpp//bbaacckkuupp..ffssBB \\

## zzffss rreecceeiivvee -dd ppoooollBB//rreecceeiivveedd << //ttmmpp//bbaacckkuupp..ffssBB

EExxaammppllee 1144 Setting User Properties The following example sets the user defined "com.example:department" property for a dataset.

## zzffss sseett ccoomm..eexxaammppllee::ddeeppaarrttmmeenntt==1122334455 ttaannkk//aaccccoouunnttiinngg

EEXXIITT SSTTAATTUUSS The following exit values are returned: 00 Successful completion. 11 An error occurred. 22 Invalid command line options were specified.

sssshh(1), mmoouunntt(8), zzppooooll(8), cchhmmoodd(1), ssttaatt(1), ffssyynncc(2), zfs.util(8)

HISTORY The zzppooooll command first appeared in Mac OS X 10.5 (Leopard).