How do you set/change kernel parameters?

[Didar Hossain]

On Sat, Sep 19, 2009 at 6:04 AM,  <pclapham at windstream.net> wrote:
> Hi, all --
>
> I am trying to load Oracle on my ubuntu server, and I need to set or change a number of kernel parameters.  Can >anybody tell me where these are to be found, and whether one edits a conf file or uses a system application to change > them?  For example, one parameter that needs to be changed is "semopm", and I can't find a listing of it anywhere in > the documentation.

The "semopm" value is set in /proc/sys/kernel/sem file. It is a kernel
"tunable" - meaning the value can be changed at runtime.

To change the values you can use the following command *as root*:

echo 250 32000 64 256 > /proc/sys/kernel/sem

The 3rd value (64) is the "semopm" setting. Please note that the above
values are arbitrary and for example only, you should use the values
recommended by your database vendor.

Once you are satified with the values you can add a line like -

kernel.sem = 250 32000 64 256

... in the /etc/sysctl.conf file to let the settings get applied on every boot.

Didar