*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->HP-UX 11i man pages -> quota (5)              


 quota(5)                                                           quota(5)

 NAME    [Toc]    [Back]
      quota - disk quotas

 DESCRIPTION    [Toc]    [Back]
      Disk quotas can be used by the system administrator to limit the
      number of files and file blocks owned by a user on a per-file-system
      basis.  Separate limits can be established for both the number of
      files (inodes) and the number of 1-Kbyte blocks for each user.  A soft
      (preferred) and a hard limit are established.

      For example, user joe_doe may have soft limits of 1000 blocks and 200
      files and hard limits of 1200 blocks and 300 files on the root file
      system (/) containing his/her HOME directory and /tmp, and soft and
      hard block limits of 100 and 120, respectively, with no explicit file
      limit (0), on the mounted file system /mnt.

      A time limit is established for each file system which determines how
      long a user is allowed to exceed the soft limit.  The default time
      limit is one week (7 days).

      When a user exceeds his/her soft limit, a warning is emitted on the
      user's terminal.  The user can continue to increase utilization over
      the soft limit until he/she either exceeds the hard limit or the
      established time limit.  Once either of these events occurs, a message
      is sent to the user's terminal and further attempts at file creation
      and/or increased block utilization will fail.  At this point, the user
      must reduce his/her use of the exceeded limit below the soft limit to
      restore normal operation.

      At login time, users exceeding quota limits are reminded (via
      login(1)) of exceeded quotas and appropriate remedial action.  The
      user can check current quota status at any time with the quota command
      (see quota(1)).

      Quota limits and utilization statistics are maintained by the
      operating system for each file system for which quotas have been
      enabled (see mount(1M) and quotaon(1M)).

      Disk quotas are established independently for each user and each file
      system via the edquota command (see edquota(1M)).  This command is
      also used to establish the limit for the amount of time users are
      permitted to exceed their soft limit.  The default time limit is 1

      Limits and usage statistics are stored statically in the file quotas
      on the root of each file system for which they are in effect.  This
      file is synchronized with information in the kernel by the quotactl()
      system call (see quotactl(2)) and whenever an affected file system is

 Hewlett-Packard Company            - 1 -   HP-UX 11i Version 2: August 2003

 quota(5)                                                           quota(5)

      Quotas can be enabled automatically at boot or mount time by adding
      the quotas option to the option list in /etc/fstab (see fstab(4) and
      mount(1M)).  By default, mount does not enable disk quotas.

      Quotas can subsequently be disabled and re-enabled with the quotaoff
      and quotaon commands (see quotaon(1M)).  When quotas are disabled, the
      kernel does not maintain usage statistics and the quotas file usage
      statistics are invalidated by file system activity.  Disabling quotas
      improves performance, but necessitates running the quotacheck command
      (see quotacheck(1M)) to update the kernel and quotas file after
      subsequently re-enabling quotas.

      The repquota command (see repquota(1M)) displays reports of current
      quota statistics.  The somewhat related, but independent, quot command
      (see quot(1M)), collects and reports disk utilization independently of
      the disk quota subsystem.

      The mount command (see mount(1M)) reports any file systems for which
      quotas are enabled.

    Data Storage Structure    [Toc]    [Back]
      The dqblk data structure (defined in <quota.h>), is used by the
      quotactl() system call (see quotactl(2)) to get or set quota
      information.  This structure contains fields that are used to store a
      user's current file and block count and quota limits for a particular
      file system.

      struct dqblk contains the following members:

           uint32_t  dqb_bhardlimit; /* maximum # of disk blocks +1 */
           uint32_t  dqb_bsoftlimit; /* preferred limit on disk blocks */
           uint32_t  dqb_curblocks;  /* current block count */
           uint32_t  dqb_fhardlimit; /* maximum # allocated files +1 */
           uint32_t  dqb_fsoftlimit; /* preferred file limit */
           uint32_t  dqb_curfiles;   /* current # allocated files */
           uint32_t  dqb_btimelimit; /* time limit for excessive block use */
           uint32_t  dqb_ftimelimit; /* time limit for excessive files */

      The dqblk64 data structure (defined in <quota.h>), is used by the
      quotactl() system call (see quotactl(2)) to get or set quota
      information for 64-bit filesystems.  This structure contains fields
      that are used to store a user's current file and block count and quota
      limits for a particular file system.  Note that VxFS 3.5 will track
      usage in the dqb64_curblocks field only up to 2 TB.

 Hewlett-Packard Company            - 2 -   HP-UX 11i Version 2: August 2003

 quota(5)                                                           quota(5)

      struct dqblk64 contains the following members:

           uint64_t  dqb64_bhardlimit; /* maximum # of disk blocks +1 */
           uint64_t  dqb64_bsoftlimit; /* preferred limit on disk blocks */
           uint64_t  dqb64_curblocks;  /* current block count */
           uint64_t  dqb64_fhardlimit; /* maximum # allocated files +1 */
           uint64_t  dqb64_fsoftlimit; /* preferred file limit */
           uint64_t  dqb64_curfiles;   /* current # allocated files */
           uint64_t  dqb64_btimelimit; /* time limit for excessive block use */
           uint64_t  dqb64_ftimelimit; /* time limit for excessive files */

      Quotas are not fully supported over NFS file systems.  However, the
      quota command is able to report quota statistics on remote NFS file
      systems for which disk quotas are in effect, if the remote system
      provides the RPC rquotad service (see rquotad(1M)).

      rquotad is provided to allow reciprocal support to other systems.

 EXAMPLES    [Toc]    [Back]
    Initial Setup
      The kernel must be reconfigured to support disk quotas; see the System
      Administration manuals.  Eligible file systems for disk quota
      enforcement are those with mount options rw and quota, as described in
      mount(1M) and fstab(4).

      For each file system for which quotas are to be enabled, perform the
      following tasks:

           1.   Mount the file system.

           2.   Add quota to the existing options list in /etc/fstab.  For
                example, change the string default for the root (/) entry to
                default,quota.  Once this is done, quotas will automatically
                be enabled for all relevant file systems on system reboot.

           3.   Create the quotas file in the mount directory of the file
                system.  For example, for the /mnt file system, run the

                       cpset /dev/null /mnt/quotas 600 root bin

           4.   Establish one or more prototype user quotas using the
                edquota command (see edquota(1M)).

                If you want a number of users on your system to have the
                same limits, use edquota to set those quotas for a prototype
                user; then use the edquota -p command to replicate those
                limits for that group of users.

 Hewlett-Packard Company            - 3 -   HP-UX 11i Version 2: August 2003

 quota(5)                                                           quota(5)

           5.   Turn on the quotas on the file system using quotaon.  For
                example, run the command

                       /usr/sbin/quotaon /mnt

           6.   Run quotacheck (see quotacheck(1M)) on the file system to
                record the current usage statistics.

    Adding a new user    [Toc]    [Back]
      To add a new user to the quota system:

           1.   Use edquota to copy the quotas of an existing user.

           2.   Run quotacheck.

    Adding a new file system to an established system    [Toc]    [Back]
      Repeat steps 1 through 5 above under "Initial Setup" for the new file

 WARNINGS    [Toc]    [Back]
      The HP-UX default is to allow chown(2).  This can interfere with the
      disk quota mechanism.  Quotas can be defeated if the chown command
      (see chown(1)) or the chown() system call (see chown(2)) is accessible
      to a user.  The setprivgrp command (see setprivgrp(1M)) can be used to
      limit access to the chown() system call so that only a specified group
      of users are permitted to use the chown command or the chown() system

      The sam command (see sam(1M)) does not yet support disk quotas.  When
      adding new users or file systems, any desired quotas must be
      established outside of sam.

      HP has added features to the original implementation to ensure
      correctness of the content of the quotas file when quotas are enabled
      by mount and disabled by umount (see mount(1M)), thus eliminating the
      need to run quotacheck (see quotacheck(1M)).  These features are
      ineffective, however, if quotaoff and quotaon (see quotaon(1M)) are
      used to control quotas.

      quotacheck should only be run on a dormant file system to ensure
      accurate usage information.  The -qv options of the fsclean command
      (see fsclean(1M)) report on the the current viability of the quota

 AUTHOR    [Toc]    [Back]
      Disk Quotas were developed by the University of California, Berkeley,
      Sun Microsystems, and HP.

 FILES    [Toc]    [Back]
      /etc/fstab            Static information about the file systems

 Hewlett-Packard Company            - 4 -   HP-UX 11i Version 2: August 2003

 quota(5)                                                           quota(5)

      /etc/mnttab           Mounted file system table

      directory/quotas      Quota statistics static storage for a file
                            system, where directory is the root of the file
                            system, as specified to the mount command (see

 SEE ALSO    [Toc]    [Back]
      chown(1), chown(2), quota(1), edquota(1M), fstab(4), mount(1M),
      quot(1M), quotacheck(1M), quotaon(1M), rquotad(1M), setprivgrp(1M),
      quotactl(2), vfsmount(2).

 Hewlett-Packard Company            - 5 -   HP-UX 11i Version 2: August 2003
[ Back ]
 Similar pages
Name OS Title
quotactl Tru64 Manipulate disk quotas
quotactl HP-UX manipulate disk quotas
quotactl Linux manipulate disk quotas
quotactl IRIX manipulate disk quotas
edquota HP-UX edit user disk quotas
edquota Tru64 Edits quotas.
disklabel Tru64 Reads and writes a disk pack label and formats disk partitions
edquota FreeBSD edit user quotas
quotactl OpenBSD manipulate filesystem quotas
quotaon OpenBSD turn filesystem quotas on and off
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service