topic Re: SHMMAX kernel parameter in Operating System - HP-UX

SHMMAX kernel parameter

sheevm — Mon, 11 Dec 2006 14:28:08 GMT

Hi,

Can someone tell me how is SGA_MAX oracle parameter relates to SHMMAX. We have 8GB physical memory in the box. What is the SHMMAX can be set to maximum? HP-UX 11iv2, rp8420 server.

Thanks
kesh

Re: SHMMAX kernel parameter

James R. Ferguson — Mon, 11 Dec 2006 14:43:24 GMT

Hi:

The 'shmmax' defaults to 1GB with a minimum value of 2048 and a maximum of 0x40000000000 (4,398,046,511,104 decimal).

http://docs.hp.com/en/B2355-60105/shmmax.5.html

Regards!

...JRF...

Re: SHMMAX kernel parameter

sheevm — Mon, 11 Dec 2006 15:10:36 GMT

Hi James,

Thanks for the response. Does it cause any issues to set the SHMMAX equal to the size of the memory?

Thanks
Raji

Re: SHMMAX kernel parameter

sheevm — Mon, 11 Dec 2006 15:12:05 GMT

James, Thanks for the response.

Does it cause any issue setting this parameter equal to the size of the physical memory?

Regards,
kesh

Re: SHMMAX kernel parameter

James R. Ferguson — Mon, 11 Dec 2006 15:18:02 GMT

Hi (again) Kesh:

Like most kernel parameters, this is a fence or limit. You could set it to a value equal to your physical memory if you want, but this doesn't make sense. You wouldn't want one process to be able to create one large shared memory segement equal to all of your physical memory --- assuming that you even could! See the manpage reference I cited for you.

Regards!

...JRF...