Provided by: xfsprogs_3.1.7_amd64 bug

NAME

       xfs_quota - manage use of quota on XFS filesystems

SYNOPSIS

       xfs_quota [ -x ] [ -p prog ] [ -c cmd ] ... [ -d project ] ... [ path ... ]

DESCRIPTION

       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.

       -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.

       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

       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) he 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.  He can use the
       editor  shell  escape  command  to  examine  his  file  space  and  remove  surplus files.
       Alternatively, using sh(1), he 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.

USER COMMANDS

       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 [ -gpu ] [ -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

       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
              IRIX  XFS,  refer  to  quotaon(1M).   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

       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 patch list  can
              come from several places - the command line, the mount table, and the /etc/projects
              file.

       report [ -gpu ] [ -bir ] [ -ahntLNU ] [ -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. 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. 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  [  -gpu  ]  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 [ -gpu ] [ -bir ] value
              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. The value argument is a
              number of seconds, but units of 'minutes', 'hours', 'days', and  'weeks'  are  also
              understood (as are their abbreviations 'm', 'h', 'd', and 'w').

       warn [ -gpu ] [ -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 [ -gpu ] [ -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 [ -gpu ] [ -f file ]
              Restore  quota  limits from a backup file.  The file must be in the format produced
              by the dump command.

       quot [ -gpu ] [ -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 ]
              Without arguments, this command lists known project names and identifiers (based on
              entries in the /etc/projects and /etc/projid files). The -c,  -C,  and  -s  options
              allow  the  directory  tree  quota  mechanism to be maintained.  -d allows to limit
              recursion level when processing  project  directories  and  -p  allows  to  specify
              project  paths  at  command  line  (  instead  of  /etc/projects ). All options are
              discussed in detail below.

DIRECTORY TREE QUOTA

       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 posibility 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

       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

       XFS  implements  delayed allocation (aka. allocate-on-flush) and this has implications for
       the quota subsystem.  Since quota accounting can only be done  when  blocks  are  actually
       allocated,  it  is  possible  to issue (buffered) writes into a file and not see the usage
       immediately updated.  Only when the data is actually written out, either via  one  of  the
       kernels flushing mechanisms, or via a manual sync(2), will the usage reported reflect what
       has actually been written.

       In addition, 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

       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

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

IRIX SEE ALSO

       quotaon(1M), xfs(4).

LINUX SEE ALSO

       warnquota(8), xfs(5).

SEE ALSO

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

                                                                                     xfs_quota(8)