Disk quota management


  With multi-user systems, administrators must protect against users
  filling the disk.  Often, users remove unneeded files only when prod-
  ded. This eventually results in a scarcity of space.  Runaway programs
  may fill up large amounts of disk space as well, often through log
  files that record errors.  It is possible to limit the amount of
  files, directories and    disk space used by a user.

  1.  Some concepts


  1.1.  Per device/partition control

  Disk quotas are managed partition by partition. There is no relation
  between each partition and quotas setup. Further, you may enable disk
  quotas on some partitions while disabling them on others.


  1.2.  User and group quotas

  You can control disk quota user per user. You can also work at the
  group level. Both quotas are set up completely independently.  A group
  with a hundred users may have a disk space quota of much less than the
  sum of the users' quotas.

  When a file is created by a user, it belongs to that user and to some
  group. The disk quotas of both the user and the group are updated.

  A user may have plenty of available disk quota, but the group may be
  out of quota. Because of that, the user won't be able to use more disk
  space while active in that group.  This will not prevent them from
  doing work in another group assuming that the space is available.
  However, they will need to switch to that group before this can occur.


  1.3.  Group quotas and members default quotas

  Linuxconf lets you manage quotas with great flexibility. While you can
  configure the quota limits user by user, most administrators will
  choose to operate more globally. Further, linuxconf lets you partially
  fill quota specifications. This lets you use some defaults for a user
  and override only a single specification (the maximum files allowed
  for example).


  1.4.  Disk quota information

  You can control two aspects with disk quotas: (1) the number of files
  and directories owned by a user (or group) and (2) the amount of disk
  space owned. Both options are controlled separately. It is possible to
  have no limit on one, while enforcing some limits on the other.

  Each aspect is controlled by three parameters:


  +o  Soft limit

     The soft limit is a proposed operational limit. The user/group may
     exceed this limit, but only for a limited amount of time.

  +o  Hard limit

     This limit can't be exceed.

  +o  Grace period

     This is the length of time the user/group may exceed the soft
     limit. It defaults to 7 days, and is expressed in a
     days:hours:minutes:seconds format.



  1.5.  Possible values for a limit

  A given limit may have three values:


  +o  0

     This means no limits.

  +o  -1

     This means unspecified. The effective value is inherited from the
     defaults.

  +o  Some value greater than 0

     This is a limit. For disk space, this is expressed in kilobytes,
     and is true whatever the block size used on the disk. Linuxconf
     will translate the kilobytes to fit the disk subsystem
     requirements.


  1.6.  Effective quotas for users

  Disk quotas for a user are influenced by three setups:


  +o  The user records

     Those records are visible in the user account dialog. One record
     exists per partition with user quotas enabled.

  +o  The defaults for group members

     Don't confuse this with group quotas. You can set up default values
     for disk quotas which apply directly to the members of the group.
     You modify these defaults right in the group account dialog. One
     record exists per partition with user quotas enabled.

  +o  General default values

     One record per partition provides the base defaults.  Often this
     will be the only record modified with all users inheriting these
     values.


  1.7.  Effective quotas for groups

  Disk quotas for a group are influenced by two setups:


  +o  The group records

     These records are visible in the group account dialog. One record
     exists per partition with group quota enabled.

  +o  General default values

     One record per partition provides the base defaults.  Often this
     will be the only record modified with all groups inheriting these
     values.


  2.  Enabling disk quotas



  You have to enable disk quotas on each partition where you want this
  level of control. This is done in the "Filesystem configurator." Pick
  the menu "Access local drive" and then pick each partition where you
  want to enable disk quotas. In the dialog, you will find a checkbox
  for user quotas and another for group quotas.

  Again, these quotas (user and group) are completely independent and
  may be enabled separately.


  3.  Related commands

  Here are the different commands you may want to use to manipulate disk
  quotas:


  +o  quotaon,quotaoff

     This lets you turn on and off quotas on a partition.

  +o  repquota

     This prints a status report for the different users or groups.

  +o  quotacheck

     This checks a partition and updates the status of each group and
     user. This command is normally run right after an fsck at boot
     time.


  +o  edquota

     This is a bare bones quota management utility. It allows you to
     edit a user record or group record directly. DO NOT USE THIS. It
     has no concept of defaults and any changes made with it may be
     overwritten by Linuxconf.