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I thought about different params, sorry. look under
there are entries for shm and sem. You can use echo "param">/proc/sys/kernel/file
Let me look how to get it set permanently on boot up, instead of echoing the parameters into /proc
On RedHat, there's a handy file called /etc/sysctl.conf into which you can put the options in sysctl format.
Essentially, sysctl format is the same as the /proc/sys/ layout, but with the '/' changed to a '.'.
So for the max SvsV shm segment size, you can either play with the file:
Or the sysctl variable:
However, exactly what this actually is is beyond my knowledge by quite a way. Some of these cannot be altered, some can be but will have no effect. Some will actually work, and changing others may force a kernel panic.
They're documented, at least usually, in the /usr/src/linux-*/Documentation/sysctl/ directory of your kernel source tree, or in the /usr/share/doc/kernel-*/sysctl/ if you have installed the kernel-doc package.
If you only change the sysctl settings in the file /etc/sysctl.conf, then yes, those are only acted upon on boot. (This file exists on RedHat derivatives, and Debian derivatives - I think it's pretty much universal).
If you only change them in the /proc/sys filesystem, then no, those are acted upon immediately, and the new values are lost when you reboot.
So really, you need to do both.
Incidentally, "cat /proc/sys/....." will give you the current value that's actually being used - I don't think we ever made this clear - stuff in /proc/ isn't on your hard disk, it's a kind of view into the kernel of its current structures and Stuff. Changing the values here (usually with "echo 1 >/proc/sys/..." or similar) actually changes the live setting in the kernel, and not any file at all. Reading the file is actually reading the setting directly from the kernel.
For obvious reasons, you can't create a new setting by creating a new file. Although that'd be a very impressive patch. :-)