quotacheck

Scan a file system for disk usage.

Syntax
      quotacheck [ -gubcfinvdMmR ] [ -F quota-format ] -a | filesystem

Options
   -b, --backup
           Forces quotacheck to make backups of the quota file before writing the new data.

   -v, --verbose
           quotacheck reports its operation as it progresses. Normally it operates silently.
           If the option is specified twice, also the current directory is printed (note that printing can slow
           down the scan measurably).

   -d, --debug
           Enable debugging mode.
           It will result in a lot of information which can be used in debugging the program.
           The output is very verbose and the scan will be slow.

   -u, --user
           Only user quotas listed in /etc/mtab or on the filesystems specified are to be checked.
           This is the default action.

   -g, --group
           Only group quotas listed in /etc/mtab or on the filesystems specified are to be checked.

   -c, --create-files
           Don't read existing quota files. Just perform a new scan and save it to disk.
           quotacheck also skips scanning of old quota files when they are not found.

   -f, --force
           Forces checking and writing of new quota files on filesystems with quotas enabled.
           This is not recommended as the created quota files may be out of sync.

   -M, --try-remount
           This flag forces checking of filesystem in read-write mode if a remount fails.
           Do this only when you are sure no process will write to a filesystem while scanning.

   -m, --no-remount
           Don't try to remount filesystem read-only. See comment with option -M.

   -i, --interactive
           Interactive mode. By default quotacheck exits when it finds an error.
           In interactive mode user is asked for input instead. See option -n.

   -n, --use-first-dquot
           If the quota files become corrupted, it is possible for duplicate entries for a single user
           or group ID to exist. Normally in this case, quotacheck exits or asks user for input.
           When this option is set, the first entry found is always used (this option works in interactive mode too).

   -F, --format=format-name
           Check and fix quota files of specified format (ie. don't perform format auto-detection).
           This is recommended as detection might not work well on corrupted quota files.
           Possible format names are: vfsold Original quota format with 16-bit UIDs / GIDs,
           vfsv0 Quota format with 32-bit UIDs / GIDs, 64-bit space usage, 32-bit inode usage and limits,
           vfsv1 Quota format with 64-bit quota limits and usage, rpc (quota over NFS),
           xfs (quota on XFS filesystem)

   -a, --all
           Check all mounted non-NFS filesystems in /etc/mtab

   -R, --exclude-root
           When used together with the -a option, all filesystems except for the root filesystem are checked for quotas.

quotacheck examines each filesystem, builds a table of current disk usage, and compares this table against that recorded in the disk quota file for the filesystem (this step is ommitted if option -c is specified). If any inconsistencies are detected, both the quota file and the current system copy of the incorrect quotas are updated (the latter only occurs if an active filesystem is checked which is not advised).

By default, only user quotas are checked. quotacheck expects each filesystem to be checked to have quota files named [a]quota.user and [a]quota.group located at the root of the associated filesystem. If a file is not present, quotacheck will create it.

If the quota file is corrupted, quotacheck tries to save as much data as possible. Rescuing data may need user intervention. With no additional options quotacheck will simply exit in such a situation. When in interactive mode (option -i) , the user is asked for advice. Advice can also be provided from command line (see option -n) , which is useful when quotacheck is run automatically (ie. from script) and failure is unacceptable.

quotacheck should be run each time the system boots and mounts non-valid filesystems. This is most likely to happen after a system crash. It is strongly recommended to run quotacheck with quotas turned off for the filesystem. Otherwise, possible damage or loss to data in the quota files can result. It is also unwise to run quotacheck on a live filesystem as actual usage may change during the scan. To prevent this, quotacheck tries to remount the filesystem read-only before starting the scan.

After the scan is done it remounts the filesystem read-write. You can disable this with option -m. You can also make quotacheck ignore the failure to remount the filesystem read-only with option -M.

Quotacheck should only be run as Super User. Non-priviliged users are presumably not allowed to read all the directories on the given file system.

Files
aquota.user or aquota.group
Located at filesystem root with quotas (version 2 quota, non-XFS filesystems)

quota.user or quota.group
Located at filesystem root with quotas (version 1 quota, non-XFS filesystems)

/etc/mtab
Names and locations of mounted filesystems

"In the factory we make cosmetics. In the store we sell hope" ~ Charles Revson

Related linux commands:

quota - Display disk usage and limits.
fstab, quotaon, quotaoff, edquota, repquota.
fsck - File system consistency check and repair.
efsck, e2fsck, xfsck.
ulimit - Limit user resources.
Equivalent Windows command: FSUTIL quota - File and Volume utilities.


 
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