topic Re: shmmax equal to RAM in Operating System - HP-UX

shmmax equal to RAM

Ramones — Tue, 29 Apr 2008 11:09:22 GMT

Hi
What could be the impact of increasing the kernel parameter shmmax to be the same size of system RAM?

Thanks,
R

Re: shmmax equal to RAM

Court Campbell — Tue, 29 Apr 2008 11:12:16 GMT

No impact at all.

Re: shmmax equal to RAM

David Child_1 — Tue, 29 Apr 2008 12:52:02 GMT

There is no direct impact, but there could be side effects if your DBAs don't think things through and decide to use all that space.

David

Re: shmmax equal to RAM

skt_skt — Tue, 29 Apr 2008 14:00:26 GMT

Here is a SHMMAX rule of thumb.

The maximum usable setting for this paramter is 25 percent of memory. Memory in this case is defined as RAM plus swap.

Re: shmmax equal to RAM

Sajjad Sahir — Wed, 30 Apr 2008 05:13:20 GMT

Dear Ramones

the answer is no

thanks and regards

Sajjad

Re: shmmax equal to RAM

Sajjad Sahir — Wed, 30 Apr 2008 05:21:53 GMT

Dear Ramones
more clarification

how much RAM and swap in u system and what about free memory, which database is using what about the status
Dear my opinion is please don't set shared memory mmax higher than your RAM plus SWAP.
before changing any parameter, be sure that u know what is the effect on the system performance.

thanks and regards

sajjad