Problem with > 256 apache processes - Solved
We have run into a strange problem with our apache processes.
If we run the serverlimit at 256 the server runs with load < 5 all the time and has a system usage < 6% and idles 50%.
== top snippet ==
Tasks: 233 total, 5 running, 226 sleeping, 0 stopped, 2 zombie
Cpu(s): 42.8%us, 6.7%sy, 0.7%ni, 45.6%id, 0.2%wa, 0.0%hi, 3.9%si, 0.0%st
Mem: 2059792k total, 2029916k used, 29876k free, 38488k buffers
Swap: 1911724k total, 3252k used, 1908472k free, 1676096k cached
== /top snippet ==
The server is a regular webserver which runs Apache 2.2.3 and php 5.1.6. It opens a connection to our database-server per connection and also it might use a nfs disk if the user uploads something.
If we use more than 256 connections the load goes through the roof, the %sy usage goes up to around 40-50% and the usertime goes down to 20% and the rest is idletime (probably doing context switches).
The context switches also jumps from arount 10k to 150k as soon as over 256 processes are reached.
If we look at our cacti-graphs the load seems to be instantanious, from ~5 to ~150 in a minute.
I have no idea on how to debug this problem, any help would be appreciated.
Dell PowerEdge 1950
2 x Dual Core Intel® Xeon® 5110, 4MB Cache, 1.6GHz
Last edited by yepp; 11-13-2006 at 01:19 AM.