tunrestore Command

The tunrestore command is used to restore all the parameters from a file.

The following is the syntax for the tunrestore command:

tunrestore -R | [-r] -f filename

For example, the following will change the current values for all tunable parameters present in the file if ranges, dependencies, and incremental parameter rules are all satisfied.

tunrestore -f mytunable

tunrestore -f /etc/tunables/mytunable

In case of problems, only the changes possible will be made.

For example, the following will change the reboot values for all tunable parameters present in the file if ranges and dependencies rules are all satisfied. In other words, they will be copied to the /etc/tunables/nextboot file.

tunrestore -r -f mytunable

If changes to parameters of type Bosboot are detected, the user will be prompted to run the bosboot command.

The following command can only be called from the /etc/inittab file and changes tunable parameters to values from the /etc/tunables/nextboot file.

tunrestore -R

Any problem found or change made is logged in the /etc/tunables/lastboot.log file. A new /etc/tunables/lastboot file is always created with the list of current values for all parameters. Any change to restricted tunables from their default values will cause the addition of an error log entry identifying the list of these modified tunables.

If filename does not exist, an error message displays. If the nextboot file does not exist, an error message displays if -r was used. If -R was used, all the tuning parameters of a type other than Bosboot will be set to their default value, and a nextboot file containing only an info stanza will be created. A warning will also be logged in the lastboot.log file.

Except when -r is used, parameters requiring a call to bosboot and a reboot are not changed, but an error message is displayed to indicate they could not be changed. When -r is used, if any parameter of type Bosboot needs to be changed, the user will be prompted to run bosboot. Parameters missing from the file are simply left unchanged, except when -R is used, in which case missing parameters are set to their default values. If the file contains multiple entries for a parameter, only the first entry will be applied, and a warning will be displayed or logged (if called with -R).