How to set ulimit values

原始链接：https://access.redhat.com/solutions/61334

How to set ulimit values

Environment

• Red Hat Enterprise Linux 5
• Red Hat Enterprise Linux 6
• Red Hat Enterprise Linux 7

Issue

• 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:

    • an 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 the two values:

    • ”soft” for enforcing the soft limits
    • “hard” for enforcing 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
    • 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

Diagnostic Steps

• To improve performance, we can safely set the limit of processes for the super-user root to be unlimited. Edit the .bashrc file vi /root/.bashrc and add the following line:

# vi /root/.bashrc
ulimit -u unlimited

• Exit and re-login from the terminal for the change to take effect.
• Can also run ulimit -u unlimited at the command prompt instead of adding it to the /root/.bashrc file.