Tweak Apache to handle large traffic and large process
If your site isbuilt from heavy php files like us, you're probably using apache's prefork model (instead of a mpm such as worker, which would be more efficient but cause stability problems with zend engine) and as your site grows, yu apache will start forking way too many threads.
As a result you may end up forcing hte limits of your operating system's default configurations.
At Linux, there are 2 important sysctl configurations that can affect the performance of your site in high-load sitatuons; they are: kernel.shmall and kernel.shmmax
You can use their current values by typing:
touch /proc/sys/kernel/shmall
and
touch /proc/sys/kernel/shmmax
shmmaz should be around 32MB.
The solution is as easy as increasing it, and fortunately that doesn't requre kernel recompilation.
Here is what you should type:
echo 134217728 >/proc/sys/kernel/shmmax
aand
echo 134217728 >/proc/sys/kernel/shmall
Now both are 128MB and you're all set. You may want to save these changes in /etc/sysconfig.ctl as well and to see all values, type in sysctl -a
Hope this helps,
