topic Re: kernel tuning RHEL3 in Operating System - Linux

kernel tuning RHEL3

Manuela Italia — Tue, 06 Jun 2006 08:44:19 GMT

Hi

I'm tuning kernel parameters of a Red Hat Enterprise Linux AS release 3 (Taroon Update 7).
I tuned parameters with "sysctl" command, but i'm not able to modify the value of shmseg and shmmin, because there are not files
/proc/sys/kernel/shmseg and /proc/sys/kernel/shmmin and
# sysctl -w kernel.shmseg=10
error: 'kernel.shmseg' is an unknown key.

I don't have kernel source, because I'm using the installation kernel 2.4.21-40.ELsmp.

How can I enable these parameters and change their value without rebuilt a new kernel?

Thanks a lot!

Manuela

Re: kernel tuning RHEL3

Vitaly Karasik_1 — Tue, 06 Jun 2006 09:31:20 GMT

which parameters exactly do you need to tune? there is no shmmin, there is shmmni:

kernel.shmmni = 4096
kernel.shmall = 2097152
kernel.shmmax = 33554432

Re: kernel tuning RHEL3

Manuela Italia — Tue, 06 Jun 2006 09:53:05 GMT

Hi
I'm not able to tune parameters "shmmin" and "shmseg".
I tuned without problem the other parameters.
I got these parameters from "Oracle Enterprise Manager Grid Control requirements guide"

thank you!

Manuela

Re: kernel tuning RHEL3

Vitaly Karasik_1 — Wed, 07 Jun 2006 01:20:36 GMT

Well, after some googling I understand that shmmin & shmseg isn't a type as I suspected (sorry for that!).

But, according to http://www.puschitz.com/InstallingOracle10g.shtml, shmmin isn't a kernel parameter and shmseg is hardcoded, but default is enough:

shmmin = 1 (To verify, execute: ipcs -lm |grep "min seg size")
shmseg = 10 (It's hardcoded in the kernel - the default is much higher)

Re: kernel tuning RHEL3

Manuela Italia — Wed, 07 Jun 2006 02:48:31 GMT

thanks a lot!