How to set ulimit values

Resolution

• Settings in /etc/security/limits.conf take the following form:

  # vi /etc/security/limits.conf
  #<domain>        <type>  <item>  <value>
  
  *               -       core             <value>
  *               -       data             <value>
  *               -       priority         <value>
  *               -       fsize            <value>
  *               soft    sigpending       <value> eg:57344
  *               hard    sigpending       <value> eg:57444
  *               -       memlock          <value>
  *               -       nofile           <value> eg:1024
  *               -       msgqueue         <value> eg:819200
  *               -       locks            <value>
  *               soft    core             <value>
  *               hard    nofile           <value>
  @<group>        hard    nproc            <value>
  <user>          soft    nproc            <value>
  %<group>        hard    nproc            <value>
  <user>          hard    nproc            <value>
  @<group>        -       maxlogins        <value>
  <user>          hard    cpu              <value>
  <user>          soft    cpu              <value>
  <user>          hard    locks            <value>
  

  • <domain> can be:

    • a user name
    • a group name, with @group syntax
    • the wildcard *, for default entry
    • the wildcard %, can be also used with %group syntax, for maxlogin limit

  • <type> can have two values:

    • soft for enforcing the soft limits
    • hard for enforcing hard limits
    • - for enforcing soft as well as hard limits

  • <item> can be one of the following:

    • core - limits the core file size (KB)
    • data - max data size (KB)
    • fsize - maximum filesize (KB)
    • memlock - max locked-in-memory address space (KB)
    • nofile - max number of open files
    • rss - max resident set size (KB)
    • stack - max stack size (KB)
    • cpu - max CPU time (MIN)
    • nproc - max number of processes (see note below)
    • as - address space limit (KB)
    • maxlogins - max number of logins for this user
    • maxsyslogins - max number of logins on the system
    • priority - the priority to run user process with
    • locks - max number of file locks the user can hold
    • sigpending - max number of pending signals
    • msgqueue - max memory used by POSIX message queues (bytes)
    • nice - max nice priority allowed to raise to values: [-20, 19]
    • rtprio - max realtime priority

• Exit and re-login from the terminal for the change to take effect.

• More details can be found from below command:

  # man limits.conf
  

• Note that the nproc setting can no longer be set in limits.conf. Please use /etc/security/limits.d/90-nproc.conf instead. Setting nproc in /etc/security/limits.conf has no effect in Red Hat Enterprise Linux.