How to set ulimit values

以你之姓@ 2024-02-20 11:35 56阅读 0赞

### Environment ###

*  Red Hat Enterprise Linux (RHEL)

### Issue ###

*  How to set `ulimit` values

### Resolution ###

*  Settings in `/etc/security/limits.conf` take the following form:
    
    [Raw][]
    
        # 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:
    
    [Raw][]
    
        # 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.][Setting nproc in _etc_security_limits.conf has no effect in Red Hat Enterprise Linux.]

### 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 and add the following line:
    
    [Raw][]
    
        # 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 file `/root/.bashrc`.

[Raw]: https://access.redhat.com/solutions/61334#
[Setting nproc in _etc_security_limits.conf has no effect in Red Hat Enterprise Linux.]: https://access.redhat.com/solutions/146233