Modifications
AIX® provides a flexible and centralized mode for setting most of the AIX kernel tuning parameters.
It is now possible to make permanent changes without editing any rc files. This is achieved by placing the reboot values for all tunable parameters in a new /etc/tunables/nextboot stanza file. When the machine is rebooted, the values in that file are automatically applied.
The /etc/tunables/lastboot stanza file is automatically generated with all the values that were set immediately after the reboot. This provides the ability to return to those values at any time. The /etc/tunables/lastboot.log log file records any changes made or that could not be made during reboot.
| Command | Purpose |
|---|---|
| tunsave | Saves values to a stanza file |
| tunchange | Updates values in a stanza file |
| tunrestore | Applies applicable parameter values that are specified in a file |
| tuncheck | Validates files that are created manually |
| tundefault | Resets tunable parameters to their default values |
All of the above commands work on both current and reboot tunables parameters values. For more information, see their respective man pages.
For more information about any of these kernel tuning parameter modifications, see the Kernel Tuning section in Performance Tools Guide and Reference.