Linux distributions typically use the /sbin/sysctl command to set kernel parameters. See "man sysctl" for more information.

SEMMNU is a kernel parameter for Unix System V. It doesn't exist in Linux. In Linux kernels, the semaphore parameters are set as four values for the kernel.sem parameter.

If you run "/sbin/sysctl -a | grep sem" (as root), you should see something like:

kernel.sem = 250        256000  100     1536

The four values correspond to semmsl (maximum number of semaphores in a set), semmns (maximum number of semaphores in all sets), semopm (maximum number of operations in a semop call), and semmni (maximum number of semaphore sets). Linux doesn't have a way to set semmnu (maximum number of semaphore undo structures), because the Linux kernel doesn't use it.

You can change the other parameters temporarily using sysctl, or set new values for them when the system boots using /etc/sysctl.conf. But whatever your problem is, it won't be solved by changing semmnu, because that can't be done (and would have no effect anyway) in Linux.