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NAME | SYNOPSIS | DESCRIPTION | QUOTA OVERVIEW | USER COMMANDS | QUOTA ADMINISTRATION | ADMINISTRATOR COMMANDS | DIRECTORY TREE QUOTA | EXAMPLES | CAVEATS | BUGS | FILES | IRIX SEE ALSO | LINUX SEE ALSO | SEE ALSO | COLOPHON |
xfs_quota(8) System Manager's Manual xfs_quota(8)
xfs_quota - manage use of quota on XFS filesystems
xfs_quota [ -x ] [ -f ] [ -p prog ] [ -c cmd ] ... [ -d project ] ...
[ -D projects_file ] [ -P projid_file ] [ path ... ]
xfs_quota -V
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.
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.
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.
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).
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
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 [ -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 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.
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.
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
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.
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).
/etc/projects Mapping of numeric project identifiers to
directories trees.
/etc/projid Mapping of numeric project identifiers to project
names.
quotaon(1M), xfs(4).
warnquota(8), xfs(5).
df(1), mount(1), sync(2), projid(5), projects(5).
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, see
⟨http://oss.sgi.com/bugzilla/buglist.cgi?product=XFS⟩. This page was
obtained from the project's upstream Git repository
⟨git://oss.sgi.com/xfs/cmds/xfsprogs⟩ on 2017-07-05. 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)