topic Confirming the impact of changing kernel parameter in Operating System - HP-UX

Confirming the impact of changing kernel parameter

Srikanth Arunachalam — Thu, 09 Aug 2007 05:11:57 GMT

Hi,

We have a requirement that we need to modify the oracle database parameter called "processes" from the current value of 1000 to 5000. In order for this database parameter to take effect on the OS, we want to alter few of the kernel parameters. Effectively the database parameter allows 4000 more user processes in our server.

The configuration of our server is
HP-UX 11.23 ia64 (8 CPU, 64GB physical memory).
Oracle 10g rel2 software.

The current value of nproc is 4096 and we want to increase the value to 7168. Please confirm if it is fine to change the following kernel parameter.
kctune -s nproc =7168
kctune -s ksi_alloc_max = ((nproc*9)/10)
kctune -s ncsize = ((8*nproc+2048)+vx_ncsize)
kctune -s nfile = (15*nproc+2048)
kctune -s ninode = (8*nproc+2048)
kctune -s nkthread = (((nproc*7)/4)+16)
kctune -s semmnu = (nproc - 4)

An early response is much appreciated.

Thanks,
Srikanth A

Re: Confirming the impact of changing kernel parameter

whiteknight — Thu, 09 Aug 2007 05:22:08 GMT

Hi Srikanth,

The increase of value nproc is nothing much of concern. I would recommend you post the question to Oracle with the current kernel setting acceptable

11.23 the kernel tuning can be tuned dynamically (meaning without reboot)

WK.

Re: Confirming the impact of changing kernel parameter

vinu_2 — Thu, 09 Aug 2007 05:28:48 GMT

hi srikanth,

if the kernel parameter is static means you must reboot the server after rebuilding the kernel.

before changing any kernel parameter, be sure that you have taken the back up of /stand/vmunix and /stand/system files.

Thanks and regards,
Vinu

Re: Confirming the impact of changing kernel parameter

Luk Vandenbussche — Thu, 09 Aug 2007 05:58:55 GMT

You can modify nproc without any problem.

A reboot is required to activate this parameter.

Re: Confirming the impact of changing kernel parameter

Steven E. Protter — Thu, 09 Aug 2007 06:48:18 GMT

Shalom,

1.) First thing I do on systems these days is take out a lot of these forumulas. They are not realistic. Bill Hassell says so, so I do it.

2.) The only real way to test impact is to try the parametr change on a test system. That will at least insure that you don't blow up the system or prevent oracle from starting.

3.) I recommend setting the value much higher than the minimum so you don't have to do it again in a few months when use of the system increases.

4.) I believe that these changes are fine and will based on my experience not have a negative impact on your system.

SEP

Re: Confirming the impact of changing kernel parameter

Srikanth Arunachalam — Thu, 09 Aug 2007 07:36:14 GMT

Thanks everybody for your reply. It works fine.

Regards,
Srikanth