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AIX ulimit and maxuproc

Question & Answer


Question

Why does "ulimit -a" now show the value of maxuproc for "processes (per user)" when it used to show unlimited?

Answer

A design change took effect in AIX 7.2 TL5 and AIX 7.3 so that ulimit shows the value set for maxuproc. Since "processes per user", or nproc, is not set in /etc/security/limits, the value shown in previous releases of AIX was always unlimited.
maxuproc is an ODM value that can be viewed with the following command:
     lsattr -El sys0 -a maxuproc
The design change ensures that ulimit shows what the actual limits are for this value.
An administrator or user can use the "chuser" command to set the nprocvalue for "maximum processes per user" in /etc/security/limits. The command allows you to set this value to ulimited, however, this is not really the case as indicated in the man page for chuser:
      nproc
            Defines the soft limit on the number of processes a user can have running
            at one time. The Value parameter is an integer equal to or greater than 1. 
            The default value is -1, which sets the limit to the maximum allowed by the
            system.
The maximum allowed by the system is defined by maxuproc.

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Document Information

Modified date:
06 July 2023

UID

ibm16561649