LIMITS.CONF(5)                                          Linux-PAM Manual                                          LIMITS.CONF(5)



NAME
       limits.conf - configuration file for the pam_limits module

DESCRIPTION
       The syntax of the lines is as follows:

       <domain> <type> <item> <value>

       The fields listed above should be filled as follows:

       <domain>

           o   a username

           o   a groupname, with @group syntax. This should not be confused with netgroups.

           o   the wildcard *, for default entry.

           o   the wildcard %, for maxlogins limit only, can also be used with %group syntax.

       <type>

           hard
               for enforcing hard resource limits. These limits are set by the superuser and enforced by the Kernel. The user
               cannot raise his requirement of system resources above such values.

           soft
               for enforcing soft resource limits. These limits are ones that the user can move up or down within the permitted
               range by any pre-existing hard limits. The values specified with this token can be thought of as default values,
               for normal system usage.

           -
               for enforcing both soft and hard resource limits together.

               Note, if you specify a type of '-' but neglect to supply the item and value fields then the module will never
               enforce any limits on the specified user/group etc. .

       <item>

           core
               limits the core file size (KB)

           data
               maximum data size (KB)

           fsize
               maximum filesize (KB)

           memlock
               maximum locked-in-memory address space (KB)

           nofile
               maximum number of open files

           rss
               maximum resident set size (KB) (Ignored in Linux 2.4.30 and higher)

           stack
               maximum stack size (KB)

           cpu
               maximum CPU time (minutes)

           nproc
               maximum number of processes

           as
               address space limit (KB)

           maxlogins
               maximum number of logins for this user except for this with uid=0

           maxsyslogins
               maximum number of logins on system

           priority
               the priority to run user process with (negative values boost process priority)

           locks
               maximum locked files (Linux 2.4 and higher)

           sigpending
               maximum number of pending signals (Linux 2.6 and higher)

           msqqueue
               maximum memory used by POSIX message queues (bytes) (Linux 2.6 and higher)

           nice
               maximum nice priority allowed to raise to (Linux 2.6.12 and higher) values: [-20,19]

           rtprio
               maximum realtime priority allowed for non-privileged processes (Linux 2.6.12 and higher)

       All items support the values -1, unlimited or infinity indicating no limit, except for priority and nice.

       If a hard limit or soft limit of a resource is set to a valid value, but outside of the supported range of the local
       system, the system may reject the new limit or unexpected behavior may occur. If the control value required is used, the
       module will reject the login if a limit could not be set.

       In general, individual limits have priority over group limits, so if you impose no limits for admin group, but one of the
       members in this group have a limits line, the user will have its limits set according to this line.

       Also, please note that all limit settings are set per login. They are not global, nor are they permanent; existing only
       for the duration of the session.

       In the limits configuration file, the '#' character introduces a comment - after which the rest of the line is ignored.

       The pam_limits module does report configuration problems found in its configuration file and errors via syslog(3).

EXAMPLES
       These are some example lines which might be specified in /etc/security/limits.conf.

           *               soft    core            0
           *               hard    rss             10000
           @student        hard    nproc           20
           @faculty        soft    nproc           20
           @faculty        hard    nproc           50
           ftp             hard    nproc           0
           @student        -       maxlogins       4


SEE ALSO
       pam_limits(8), pam.d(5), pam(8), getrlimit(2) getrlimit(3p)

AUTHOR
       pam_limits was initially written by Cristian Gafton <gaftonATredhat.com>



Linux-PAM Manual                                           03/02/2009                                             LIMITS.CONF(5)