Apache memory usage control out of control

Question

I have apache2 running on ubuntu 10.04 with 512mb ram. It all seems ok, until i start start making requests to the server. When I watch my memory usage, it jumps up about 5-10% every time I browse to another page. I am assuming this is new apache processes running to server the content. I am not bothered about that, but it doesn't come back down when I stop requesting pages.

I am using Django and wsgi if that makes any difference.

EDIT:

from: /etc/apache2/apache2.conf

Timeout 300
KeepAlive On

MaxKeepAliveRequests 100

KeepAliveTimeout 3

<IfModule mpm_prefork_module>
StartServers          1
MinSpareServers       1
MaxSpareServers       5
MaxClients           15
MaxRequestsPerChild   0
</IfModule>



<IfModule mpm_worker_module>
StartServers          2
MinSpareThreads      25
MaxSpareThreads      75
ThreadLimit          64
ThreadsPerChild      25
MaxClients          150
MaxRequestsPerChild   0
</IfModule>



<IfModule mpm_event_module>
StartServers          2
MaxClients          150
MinSpareThreads      25
MaxSpareThreads      75
ThreadLimit          64
ThreadsPerChild      25
MaxRequestsPerChild   0
</IfModule>

I already edited the mpm_prefork_module to be smaller, but that didn't fix it!

Answer 1

Can you post here what are the settings of your apache

MaxRequestsPerChild

MaxClients

also some top output or whatever you are seeing when it jumps could be great to help us understand and explain where memory is going.

Answer 2

It shouldn't come back down. Its only an issue if you're running out of memory. Otherwise most software will use as much memory as possible and keep using it.

This sounds like working as expected. A few apache children start up, consume some memory, and stay running with in the bounds of max and min spare servers.

You can browse the documentation and make more adjustments if you like. Say reduce MaxSpareServers. Then you won't have as many apache processes hanging around.