kernel parameter

[Fadia Almarei]

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

[Sergejs Svitnevs · Accepted solution]

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

[Alexander Chuzhoy]

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.

[Durgaprasad Ala]

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

[NiCK_76]

Hi Almarei,

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

NiCK

[dirk dierickx]

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.

[Wim Van den Wyngaert]

This explains it.

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

Wim