Note that existing tunable parameter values must be modified using the idtune command.
There are three different ways to use the idtune command, which are explained in the ``Usage'' section.
Only the first two values apply to string tunables. For tunables that are autotuned by default and have not had this autotuning overridden with a specific value using idtune, the values shown are for the present amount of memory. If they have been overridden, the default, minimum, and maximum are for the present amount of memory, and the current is the specified value.
If the -c option is used with the -g option, the current value in the kernel currently running is displayed; otherwise, the value that will be used in the next system build is displayed.
By default, if the parameter in the stune file has a value, you are prompted to confirm the change with the following message:
Tunable Parameter parm is currently set to old_value in /etc/conf/cf.d/stune Is it OK to change it to value? (y/n)If the parameter is autotuned by default, you are prompted to confirm the change (which will override autotuning) with the message:
Tunable Parameter parm is currently autotuned. Is it OK to change it to value? (y/n)For either of these questions, if you answer y, the change is made. Otherwise, the tunable parameter will not be changed, and the following message is displayed:
parm left at old_valueHowever, if you use the -f (force) option, the change is always made and no messages are reported.
If you use the -m (minimum) option, and there is an existing value which is greater than the desired value, no change is made and no messages are reported. This option only applies to integer tunables.
If you use the -c (current) option with the first form of the idtune command, the change applies to both stune and stune.current; otherwise, only the tunable parameter in stune is affected. Because any change made to the stune.current file will affect all the loadable kernel modules configured thereafter, it is very easy to introduce inconsistencies between the currently running kernel and the new loadable kernel modules. Therefore, you should be extremely careful when using the -c option.
If you are modifying system tunable parameters as part of a device driver or application add-on package, you might want to change parameter values without prompting Your add-on package Install script could override the existing value using the -f or -m options. However, you must be careful not to invalidate a tunable parameter modified earlier by the user or another add-on package.
Any attempt to set a parameter to a value outside the valid minimum/maximum (as given in the Mtune file) range will be reported as an error, even when using the -f or -m options. No validation is performed for string tunables.
The UNIX® system kernel must be rebuilt (using idbuild(1M)) and the system rebooted for any changes to tunable parameter values in stune to take effect.