Apache/mod_jk fails under load

[Cezar Grzelak <ce...@kinek.com>]

Hi,

I've configured a cluster of Tomcats with apache1.3.20/mod_jk and things run
fine when I have up to around 70 concurrent user sessions on the system. If
I exceed that number by generating traffic at a rate of 1 new user per
second (I'm using OpenSTA to do that) apache can't cope with the number of
requests. Each tomcat box in my cluster stays very responsive - I can verify
by going directly through tomcat's http connector. However, going through
apache becomes exceedingly slow. It's almost as if apache has some hard
limits on the number of concurrent sessions. Up to around 70 everything
works like a charm but when I double that apache just refuses to cooperate.
I'm not sure whether it's apache or mod_jk that is the limiting factor here.

Has anyone else had similar scalability problems with apache/mod_jk issues?

Thanks in advance,

cezar