mod_proxy performance with apache 2.2

Skye Poier Nott <skye@xxxxx> · Tue, 18 Mar 2008 17:51:16 -0700

Hi,

I am doing some load testing on a reverse proxy with apache 2.2 +  

mod_proxy and I'm getting terrible throughput, I was wondering if  

anyone had a suggestion.

I have the following config, all on gigabit ethernet:

1 origin server -> 2 mod_proxy servers -> 4 client simulators (flood)

The origin and proxy servers are configured with 100 name-based  

virtual hosts, the proxy servers with config like this:

<VirtualHost *:80>
        ServerName w0099.example.com
        ProxyPass / http://10.100.10.XX:80/w0099/
        ProxyPassReverse / http://10.100.10.XX:80/w0099/
</VirtualHost>

When I start up flood on the client simulators (250 clients each), I  

only get about 4 Mbit/sec out of the origin server.  I've tried  

twiddling all the settings in mod_proxy to no avail (like smax=64  

max=512 ttl=120 min=8 acquire=1)

If I set up lighttpd on the proxy servers, I fully saturate the gigE  

on the origin server (~500 Mbit/sec)

What could explain this 125x difference in performance?  Is there some  

sort of resource or lock or something contention in mod_proxy that I  

should know about?

Thanks,
Skye

smime.p7s