Kernel parameters

[Roy Shiladitya]

Hi,
we are upgrading our host from 4 CPU's to 6 CPU's, and wanted to check if there were anything in particular that needed attention as far as kernel parameters / tuning is concerned. Is there a list of parameters that definitely have to change according to the number of CPU's.Any critical CPU specific tweaks not to overlooked ? I know it would depend on our particular environment but just wanted to check.The applications / DB's / MEM / OS are all staying the same, just increasing the number of CPU's

Thanks
Roy

[Bill Hassell]

No kernel changes are needed at all. If you are using sophisticated applications or database engines that scale according to CPU count, you may need to change their config files to take advantage of the extra CPUs. Otherwise, HP-UX will make use of all the CPUs without any change.

[Steven E. Protter · Accepted solution]

Shalom,

Last time I did this no changes were required. You should always check that the kernel meets the guidelines of the applications. The vendor sometimes changes this after released based on field experience.

I'm assuming you got the CPU's because performance indicated CPU pressure, e.g. you needed them.

http://www.hpux.ws/system.perf.sh

This script set can be run before and after the upgrade to compare results. It can be adjusted to run 24 hours if you wish.

SEP

[A. Clay Stephenson]

No tuning is required but one often overlooked aspect is checking the application licensing conformance after increasing the number of CPU's. A number of applications tie the licensing to the number of CPU's so you may no longer be in compliance. While HP-UX licensing doesn't care, your HP support agreements often have a per CPU support charge.

[Roy Shiladitya]

Thanks for the replies guys
regards,
Roy