shmmax

[joe_91]

Today i wanted to change the shmmax setting on my 11.11 box and found the entry to be dynamic while on my 11.0 box it states static. All the dynamic parameters can be changed on the fly ..is this correct? does the apps have to be down or would it pick up the new value. Please advise

Thanks

Joe

[Reshma Malusare]

Hi Joe,
Static parameters after change need reboot to take effect of changes. while dyamic parameters dont require reboot.

sometimes you will find dynamic parameters to be on static on some different version. it depends on the OS version

Regards
Reshma

[Peter Godron]

Joe,
please see earlier threads:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1049933
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=939671

I would suggest restarting the applications if possible.

[Sunny Jaisinghani]

Hi Joe,

Some parameters which show status as static in one system can be dynamic in other system. there are patches available to convert a static parameter to dynamic parameter.
if you are using a higher version of OS these patches are included with it.
as new versions are released the static parameters are converted to dynamic.

So in a nutshell it depends on your OS version or the patches installed.

sunny

[Don Morris_1]

Yes, shmmax was made dynamic for 11.11. It impacts new segment creation only, so any change made will affect all future shmget() calls. There's no caching of the old value to grandfather running programs or anything.

To the point, you don't always have to restart your applications -- if you have a running application, any shmget() call it makes will be affected by the tunable change. [So yes - the applications will "pick up" the new value, but whether you need to restart them or not will depend on the application implementation... if it does a single shmget() call at start time scaled based on shmmax at that time, you'd need to restart. If it does a shmget() based on an incoming work request, etc. you would not]