Ubuntu manuals

Provided by: libpam-modules_0.99.7.1-5ubuntu1_i386

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>
 
            ·   a username
 
            ·   a groupname, with @group syntax. This should not be confused
                with netgroups.
 
            ·   the wildcard *, for default entry.
 
            ·   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-exisiting 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)
 
            stack
                maximum stack size (KB)
 
            cpu
                maximum CPU time (minutes)
 
            nproc
                maximum number of processes
 
            as
                address space limit
 
            maxlogins
                maximum number of logins for this user
 
            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)
 
            rtprio
                maximum realtime priority allowed for non-privileged processes
                (Linux 2.6.12 and higher)
 
            chroot
                the directory to chroot the user to
 
        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 its best to report configuration problems
        found in its configuration file 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
        pam_limits(8), pam.d(5), pam(8)
 

AUTHOR

        pam_limits was initially written by Cristian Gafton <gafton@redhat.com>