topic Re: kernel parameter in Operating System - Linux

kernel parameter

Fadia Almarei — Wed, 02 Mar 2005 05:03:16 GMT

Dear All
in my Redhat9 linux system I have change some kernel parameters using the command line like the shmmax,

echo `expr 1024 \* 1024 \* 1024` > /proc/sys/kernel/shmmax

and when i reboot the system the parameter return it's old value,so what should i do to keep the new value even after reboot

BR,
Fadia

Re: kernel parameter

Sergejs Svitnevs — Wed, 02 Mar 2005 06:11:02 GMT

You have to add the following line to the /etc/sysctl.conf file which is used during the boot process:

kernel.shmmax=1073741824

Adding this line to the /etc/sysctl.conf file will cause the system to change these kernel parameters after each boot using the /etc/rc.d/rc.sysinit script which is invoked by /etc/inittab.

Regards,
Sergejs

Re: kernel parameter

Alexander Chuzhoy — Wed, 02 Mar 2005 06:11:20 GMT

edit the file /etc/sysctl.conf

append a line to it:
kernel.shmmax = 1073741824
then save and reboot-you should have this setting after reboot.
Regards.

Re: kernel parameter

Durgaprasad Ala — Wed, 02 Mar 2005 13:39:55 GMT

After changing parameters in /etc/sysctl.conf,just using the command
sysctl -p will update all parameters to kernel.

Re: kernel parameter

NiCK_76 — Wed, 02 Mar 2005 21:26:50 GMT

Hi Almarei,

Append "echo `expr 1024 \* 1024 \* 1024` > /proc/sys/kernel/shmmax" to /etc/rc.local.

NiCK

Re: kernel parameter

dirk dierickx — Thu, 03 Mar 2005 02:04:34 GMT

i wouldn't go for nick's approach, the others have it right, use the sysctl config file.
in fact i never write directly to /proc anymore, but use sysctl instead which is agruably(?) safer.

Re: kernel parameter

Wim Van den Wyngaert — Thu, 03 Mar 2005 03:16:09 GMT

This explains it.

http://www.redhat.com/docs/manuals/linux/RHL-7.3-Manual/ref-guide/s1-proc-sysctl.html

Wim