Set the Kernel Parameters

To display the current values of the semaphore kernel parameters, use:

cat /proc/sys/kernel/sem

250 32000 32 4096

The four values displayed are:

• SEMMSL – maximum number of semaphores per set.

• SEMMNS – maximum number of semaphores system–wide.

• SEMOPM – maximum number of operations allowed for one semop call.

• SEMMNI – maximum number of semaphore identifiers (sets).

To adjust these values, and save them for future server restarts, edit the /etc/sysctl.conf file. For example, to increase the maximum number of semaphore identifiers to 4096, add the following line:

kernel.sem = 250 32000 32 4096

Make sure you leave one space before and after equals sign.

To make a change that lasts only until the next restart, use:

echo 250 32000 32 4096 > /proc/sys/kernel/sem