Hi,
We have a blog magazine running WPMU 2.9.1 on an Apache VPS with 4gb RAM and 2 x Intel Xeon CPU E5540 2.53Ghz.
We have about 15 000 - 20 000 visits/day
The CPU is no problem, has about 1-5% load but we are having a lot of problem with the RAM memory usage that is between 2gb and hits the roof at 4gb several times every hour making the site stop or go extremely slow.
The prefork MPM of the Apache is set up like this:
StartServers 10
MinSpareServers 5
MaxSpareServers 10
MaxClients 200
MaxRequestsPerChild 0
When I do a "ps -e" I can see that we have up to 190 Apache processes running at high loads.
If I do a "top" I can only see 20-30 of the Apache processes running(am I thinking/doing anything wrong?).
But then I anyway see that every Apache processes is each taking about 0.9% memory, occupying 4.3MB of Shared memory, about 15-35MB of reserved memory and about 255MB of virtual memory.
So I got a lot of information but do not really sure how to put it all together....
Should not 4gb be enough for our site? Or is Wordpress MU taking so much power from our system with the visitor levels we have that we need to look in to getting some more memory, if so, how much?
Any other ideas?
Would cache busting help? We have added the super cache plugin to wpmu, but perhaps using cache on the apache server would also help, or?
What I am looking for is basically some ideas and help to get our site working better...
Thanks in advance,
Rickard