Configuring Shell Limits on IBM AIX

For IBM AIX on POWER Systems (64-Bit), it is the ulimit settings that determine process memory related resource limits. Use these instructions to display and change the shell limit values if they are different from the recommended value.

Set shell limits for the Oracle Grid Infrastructure installation owner and for root. Verify that unlimited is set for both accounts either by using the smit utility or by editing the /etc/security/limits file. The root user requires these settings because the crs daemon (crsd) runs as root.

Verify that the shell limits displayed in the following table are set to the values shown:

Table A-1 Recommended Shell Limit Values

Shell Limit (As Shown in smit) Recommended Value

Soft File Descriptors

at least 1024

Hard File Descriptors

at least 65536

Number of processes (Soft)

at least 2047

Number of processes (Hard)

at least 16384

Soft STACK size

at least 10240 KB

Hard STACK size

at least 10240 KB; at most 32768 KB

Soft FILE size


Soft CPU time



This is the default value.

Soft DATA segment


Soft Real Memory size


To display the current value specified for these shell limits, and to change them if necessary

  1. Enter the following command:
    # smit chuser
  2. In the User NAME field, enter the user name of the Oracle software owner, for example oracle.
  3. Scroll down the list and verify the values shown for the limits listed in the previous table.
    If necessary, edit the existing value. To edit the values, you can use the smit utility. However, to set the value of Soft Real Memory size, you must edit the file /etc/security/limits. If you have permissions to run the smit utility, then you automatically have the permissions to edit the limits file.
  4. When you have finished making changes, press F10 to exit.