xfs_quota(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | QUOTA OVERVIEW | USER COMMANDS | QUOTA ADMINISTRATION | ADMINISTRATOR COMMANDS | DIRECTORY TREE QUOTA | EXAMPLES | CAVEATS | BUGS | FILES | SEE ALSO | COLOPHON

xfs_quota(8)             System Manager's Manual            xfs_quota(8)

NAME         top

       xfs_quota - manage use of quota on XFS filesystems

SYNOPSIS         top

       xfs_quota [ -x ] [ -f ] [ -p prog ] [ -c cmd ] ... [ -d project ]
       ... [ -D projects_file ] [ -P projid_file ] [ path ... ]
       xfs_quota -V

DESCRIPTION         top

       xfs_quota is a utility for reporting and editing various aspects
       of filesystem quota.

       The options to xfs_quota are:

       -c cmd xfs_quota commands may be run interactively (the default)
              or as arguments on the command line. Multiple -c arguments
              may be given.  The commands are run in the sequence given,
              then the program exits.

       -p prog
              Set the program name for prompts and some error messages,
              the default value is xfs_quota.

       -x     Enable expert mode.  All of the administrative commands
              (see the ADMINISTRATOR COMMANDS section below) which allow
              modifications to the quota system are available only in
              expert mode.

       -f     Enable foreign filesystem mode.  A limited number of user
              and administrative commands are available for use on some
              foreign (non-XFS) filesystems.

       -d project
              Project names or numeric identifiers may be specified with
              this option, which restricts the output of the individual
              xfs_quota commands to the set of projects specified.
              Multiple -d arguments may be given.

       -D projects_file
              Specify a file containing the mapping of numeric project
              identifiers to directory trees.  /etc/projects as default,
              if this option is none.

       -P projid_file
              Specify a file containing the mapping of numeric project
              identifiers to project names.  /etc/projid as default, if
              this option is none.

       -V     Prints the version number and exits.

       The optional path argument(s) can be used to specify mount points
       or device files which identify XFS filesystems. The output of the
       individual xfs_quota commands will then be restricted to the set
       of filesystems specified.

       This manual page is divided into two sections - firstly,
       information for users of filesystems with quota enabled, and the
       xfs_quota commands of interest to such users; and then
       information which is useful only to administrators of XFS
       filesystems using quota and the quota commands which allow
       modifications to the quota system.

       Note that common to almost all of the individual commands
       described below are the options for specifying which quota types
       are of interest - user quota (-u), group quota (-g), and/or
       project quota (-p).  Also, several commands provide options to
       operate on "blocks used" (-b), "inodes used" (-i), and/or
       "realtime blocks used" (-r).

       Many commands also have extensive online help. Use the help
       command for more details on any command.

QUOTA OVERVIEW         top

       In most computing environments, disk space is not infinite.  The
       quota subsystem provides a mechanism to control usage of disk
       space.  Quotas can be set for each individual user on any/all of
       the local filesystems.  The quota subsystem warns users when they
       exceed their allotted limit, but allows some extra space for
       current work (hard limit/soft limit).  In addition, XFS
       filesystems with limit enforcement turned off can be used as an
       effective disk usage accounting system.

   Users' View of Disk Quotas
       To most users, disk quotas are either of no concern or a fact of
       life that cannot be avoided.  There are two possible quotas that
       can be imposed - a limit can be set on the amount of space a user
       can occupy, and there may be a limit on the number of files
       (inodes) they can own.

       The quota command provides information on the quotas that have
       been set by the system administrators and current usage.

       There are four numbers for each limit:  current usage, soft limit
       (quota), hard limit, and time limit.  The soft limit is the
       number of 1K-blocks (or files) that the user is expected to
       remain below.  The hard limit cannot be exceeded.  If a user's
       usage reaches the hard limit, further requests for space (or
       attempts to create a file) fail with the "Quota exceeded"
       (EDQUOT) error.

       When a user exceeds the soft limit, the timer is enabled.  Any
       time the quota drops below the soft limits, the timer is
       disabled.  If the timer pops, the particular limit that has been
       exceeded is treated as if the hard limit has been reached, and no
       more resources are allocated to the user.  The only way to reset
       this condition, short of turning off limit enforcement or
       increasing the limit, is to reduce usage below quota.  Only the
       superuser (i.e. a sufficiently capable process) can set the time
       limits and this is done on a per filesystem basis.

   Surviving When the Quota Limit Is Reached
       In most cases, the only way for a user to recover from over-quota
       conditions is to abort whatever activity is in progress on the
       filesystem that has reached its limit, remove sufficient files to
       bring the limit back below quota, and retry the failed program.
       However, if a user is in the editor and a write fails because of
       an over quota situation, that is not a suitable course of action.
       It is most likely that initially attempting to write the file has
       truncated its previous contents, so if the editor is aborted
       without correctly writing the file, not only are the recent
       changes lost, but possibly much, or even all, of the contents
       that previously existed.
       There are several possible safe exits for a user caught in this
       situation.  They can use the editor shell escape command to
       examine their file space and remove surplus files.
       Alternatively, using sh(1), they can suspend the editor, remove
       some files, then resume it.  A third possibility is to write the
       file to some other filesystem (perhaps to a file on /tmp) where
       the user's quota has not been exceeded.  Then after rectifying
       the quota situation, the file can be moved back to the filesystem
       it belongs on.

   Default Quotas
       The XFS quota subsystem allows a default quota to be enforced for
       any user, group or project which does not have a quota limit
       explicitly set.  These limits are stored in and displayed as ID
       0's limits, although they do not actually limit ID 0.

USER COMMANDS         top

       print  Lists all paths with devices/project identifiers.  The
              path list can come from several places - the command line,
              the mount table, and the /etc/projects file.

       df     See the free command.

       quota [ -g | -p | -u ] [ -bir ] [ -hnNv ] [ -f file ] [ ID | name
              ] ...
              Show individual usage and limits, for a single user name
              or numeric user ID.  The -h option reports in a "human-
              readable" format similar to the df(1) command. The -n
              option reports the numeric IDs rather than the name. The
              -N option omits the header. The -v option outputs verbose
              information. The -f option sends the output to file
              instead of stdout.

       free [ -bir ] [ -hN ] [ -f file ]
              Reports filesystem usage, much like the df(1) utility.  It
              can show usage for blocks, inode, and/or realtime block
              space, and shows used, free, and total available.  If
              project quota are in use (see the DIRECTORY TREE QUOTA
              section below), it will also report utilisation for those
              projects (directory trees). The -h option reports in a
              "human-readable" format. The -N option omits the header.
              The -f option outputs the report to file instead of
              stdout.

       help [ command ]
              Online help for all commands, or one specific command.

       quit   Exit xfs_quota.

       q      See the quit command.

QUOTA ADMINISTRATION         top

       The XFS quota system differs to that of other filesystems in a
       number of ways.  Most importantly, XFS considers quota
       information as filesystem metadata and uses journaling to provide
       a higher level guarantee of consistency.  As such, it is
       administered differently, in particular:

       1.     The quotacheck command has no effect on XFS filesystems.
              The first time quota accounting is turned on (at mount
              time), XFS does an automatic quotacheck internally;
              afterwards, the quota system will always be completely
              consistent until quotas are manually turned off.

       2.     There is no need for quota file(s) in the root of the XFS
              filesystem.

       3.     XFS distinguishes between quota accounting and limit
              enforcement.  Quota accounting must be turned on at the
              time of mounting the XFS filesystem.  However, it is
              possible to turn on/off limit enforcement any time quota
              accounting is turned on.  The "quota" option to the mount
              command turns on both (user) quota accounting and
              enforcement.  The "uqnoenforce" option must be used to
              turn on user accounting with limit enforcement disabled.

       4.     Turning on quotas on the root filesystem is slightly
              different from the above.  For Linux XFS, the quota mount
              flags must be passed in with the "rootflags=" boot
              parameter.

       5.     It is useful to use the state to monitor the XFS quota
              subsystem at various stages - it can be used to see if
              quotas are turned on, and also to monitor the space
              occupied by the quota system itself..

       6.     There is a mechanism built into xfsdump that allows quota
              limit information to be backed up for later restoration,
              should the need arise.

       7.     Quota limits cannot be set before turning on quotas on.

       8.     XFS filesystems keep quota accounting on the superuser
              (user ID zero), and the tool will display the superuser's
              usage information.  However, limits are never enforced on
              the superuser (nor are they enforced for group and project
              ID zero).

       9.     XFS filesystems perform quota accounting whether the user
              has quota limits or not.

       10.    XFS supports the notion of project quota, which can be
              used to implement a form of directory tree quota (i.e. to
              restrict a directory tree to only being able to use up a
              component of the filesystems available space; or simply to
              keep track of the amount of space used, or number of
              inodes, within the tree).

ADMINISTRATOR COMMANDS         top

       path [ N ]
              Lists all paths with devices/project identifiers or set
              the current path to the Nth list entry (the current path
              is used by many of the commands described here, it
              identifies the filesystem toward which a command is
              directed).  The path list can come from several places -
              the command line, the mount table, and the /etc/projects
              file.

       report [ -gpu ] [ -bir ] [ -ahntlLNU ] [ -f file ]
              Report filesystem quota information.  This reports all
              quota usage for a filesystem, for the specified quota type
              (u/g/p and/or blocks/inodes/realtime).  It reports blocks
              in 1KB units by default. The -h option reports in a
              "human-readable" format similar to the df(1) command. The
              -f option outputs the report to file instead of stdout.
              The -a option reports on all filesystems. By default,
              outputs the name of the user/group/project. If no name is
              defined for a given ID, outputs the numeric ID instead.
              The -n option outputs the numeric ID instead of the name.
              The -L and -U options specify lower and upper ID bounds to
              report on.  If upper/lower bounds are specified, then by
              default only the IDs will be displayed in output; with the
              -l option, a lookup will be performed to translate these
              IDs to names. The -N option reports information without
              the header line. The -t option performs a terse report.

       state [ -gpu ] [ -av ] [ -f file ]
              Report overall quota state information.  This reports on
              the state of quota accounting, quota enforcement, and the
              number of extents being used by quota metadata within the
              filesystem. The -f option outputs state information to
              file instead of stdout. The -a option reports state on all
              filesystems and not just the current path.

       limit [ -g | -p | -u ] bsoft=N | bhard=N | isoft=N | ihard=N |
              rtbsoft=N | rtbhard=N -d | id | name
              Set quota block limits (bhard/bsoft), inode count limits
              (ihard/isoft) and/or realtime block limits
              (rtbhard/rtbsoft). The -d option (defaults) can be used to
              set the default value that will be used, otherwise a
              specific user/group/project name or numeric identifier
              must be specified.

       timer [ -g | -p | -u ] [ -bir ] value [ -d | id | name ]
              Allows the quota enforcement timeout (i.e. the amount of
              time allowed to pass before the soft limits are enforced
              as the hard limits) to be modified. The current timeout
              setting can be displayed using the state command.
              When setting the default timer via the -d option, or for
              id 0, or if no argument is given after value the value
              argument is a number of seconds indicating the relative
              amount of time after soft limits are exceeded, before hard
              limits are enforced.
              When setting any other individual timer by id or name, the
              value is the number of seconds from now, at which time the
              hard limits will be enforced.  This allows extending the
              grace time of an individual user who has exceeded soft
              limits.
              For value, units of 'minutes', 'hours', 'days', and
              'weeks' are also understood (as are their abbreviations
              'm', 'h', 'd', and 'w').

       warn [ -g | -p | -u ] [ -bir ] value -d | id | name
              Allows the quota warnings limit (i.e. the number of times
              a warning will be send to someone over quota) to be viewed
              and modified. The -d option (defaults) can be used to set
              the default time that will be used, otherwise a specific
              user/group/project name or numeric identifier must be
              specified.  NOTE: this feature is not currently
              implemented.

       enable [ -gpu ] [ -v ]
              Switches on quota enforcement for the filesystem
              identified by the current path.  This requires the
              filesystem to have been mounted with quota enabled, and
              for accounting to be currently active. The -v option
              (verbose) displays the state after the operation has
              completed.

       disable [ -gpu ] [ -v ]
              Disables quota enforcement, while leaving quota accounting
              active. The -v option (verbose) displays the state after
              the operation has completed.

       off [ -gpu ] [ -v ]
              Permanently switches quota off for the filesystem
              identified by the current path.  Quota can only be
              switched back on subsequently by unmounting and then
              mounting again.

       remove [ -gpu ] [ -v ]
              Remove any space allocated to quota metadata from the
              filesystem identified by the current path.  Quota must not
              be enabled on the filesystem, else this operation will
              report an error.

       dump [ -g | -p | -u ] [ -f file ]
              Dump out quota limit information for backup utilities,
              either to standard output (default) or to a file.  This is
              only the limits, not the usage information, of course.

       restore [ -g | -p | -u ] [ -f file ]
              Restore quota limits from a backup file.  The file must be
              in the format produced by the dump command.

       quot [ -g | -p | -u ] [ -bir ] [ -acnv ] [ -f file ]
              Summarize filesystem ownership, by user, group or project.
              This command uses a special XFS "bulkstat" interface to
              quickly scan an entire filesystem and report usage
              information.  This command can be used even when
              filesystem quota are not enabled, as it is a full-
              filesystem scan (it may also take a long time...). The -a
              option displays information on all filesystems. The -c
              option displays a histogram instead of a report. The -n
              option displays numeric IDs rather than names. The -v
              option displays verbose information. The -f option send
              the output to file instead of stdout.

       project [ -cCs [ -d depth ] [ -p path ] id | name ]
              The -c, -C, and -s options allow the directory tree quota
              mechanism to be maintained.  -d allows one to limit
              recursion level when processing project directories and -p
              allows one to specify project paths at command line (
              instead of /etc/projects ). All options are discussed in
              detail below.

DIRECTORY TREE QUOTA         top

       The project quota mechanism in XFS can be used to implement a
       form of directory tree quota, where a specified directory and all
       of the files and subdirectories below it (i.e. a tree) can be
       restricted to using a subset of the available space in the
       filesystem.

       A managed tree must be setup initially using the -s option to the
       project command. The specified project name or identifier is
       matched to one or more trees defined in /etc/projects, and these
       trees are then recursively descended to mark the affected inodes
       as being part of that tree.  This process sets an inode flag and
       the project identifier on every file in the affected tree.  Once
       this has been done, new files created in the tree will
       automatically be accounted to the tree based on their project
       identifier.  An attempt to create a hard link to a file in the
       tree will only succeed if the project identifier matches the
       project identifier for the tree.  The xfs_io utility can be used
       to set the project ID for an arbitrary file, but this can only be
       done by a privileged user.

       A previously setup tree can be cleared from project quota control
       through use of the project -C option, which will recursively
       descend the tree, clearing the affected inodes from project quota
       control.

       Finally, the project -c option can be used to check whether a
       tree is setup, it reports nothing if the tree is correct,
       otherwise it reports the paths of inodes which do not have the
       project ID of the rest of the tree, or if the inode flag is not
       set.

       Option -d can be used to limit recursion level (-1 is infinite, 0
       is top level only, 1 is first level ... ).  Option -p adds
       possibility to specify project paths in command line without a
       need for /etc/projects to exist. Note that if projects file
       exists then it is also used.

EXAMPLES         top

       Enabling quota enforcement on an XFS filesystem (restrict a user
       to a set amount of space).

            # mount -o uquota /dev/xvm/home /home
            # xfs_quota -x -c 'limit bsoft=500m bhard=550m tanya' /home
            # xfs_quota -x -c report /home

       Enabling project quota on an XFS filesystem (restrict files in
       log file directories to only using 1 gigabyte of space).

            # mount -o prjquota /dev/xvm/var /var
            # echo 42:/var/log >> /etc/projects
            # echo logfiles:42 >> /etc/projid
            # xfs_quota -x -c 'project -s logfiles' /var
            # xfs_quota -x -c 'limit -p bhard=1g logfiles' /var

       Same as above without a need for configuration files.

            # rm -f /etc/projects /etc/projid
            # mount -o prjquota /dev/xvm/var /var
            # xfs_quota -x -c 'project -s -p /var/log 42' /var
            # xfs_quota -x -c 'limit -p bhard=1g 42' /var

CAVEATS         top

       The XFS allocation mechanism will always reserve the maximum
       amount of space required before proceeding with an allocation.
       If insufficient space for this reservation is available, due to
       the block quota limit being reached for example, this may result
       in the allocation failing even though there is sufficient space.
       Quota enforcement can thus sometimes happen in situations where
       the user is under quota and the end result of some operation
       would still have left the user under quota had the operation been
       allowed to run its course.  This additional overhead is typically
       in the range of tens of blocks.

       Both of these properties are unavoidable side effects of the way
       XFS operates, so should be kept in mind when assigning block
       limits.

BUGS         top

       Quota support for filesystems with realtime subvolumes is not yet
       implemented, nor is the quota warning mechanism (the Linux
       warnquota(8) tool can be used to provide similar functionality on
       that platform).

FILES         top

       /etc/projects
              Mapping of numeric project identifiers to directories
              trees.
       /etc/projid
              Mapping of numeric project identifiers to project names.

SEE ALSO         top

       df(1), mount(1), sync(2), projid(5), projects(5).  xfs(5).
       warnquota(8),

COLOPHON         top

       This page is part of the xfsprogs (utilities for XFS filesystems)
       project.  Information about the project can be found at 
       ⟨http://xfs.org/⟩.  If you have a bug report for this manual page,
       send it to linux-xfs@vger.kernel.org.  This page was obtained
       from the project's upstream Git repository
       ⟨https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git⟩ on
       2021-04-01.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-03-12.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

                                                            xfs_quota(8)

Pages that refer to this page: projects(5)projid(5)xfsdump(8)xfs_io(8)xfsrestore(8)