[Linux-cluster] GFS and server performance = Application

[isplist at logicore.net]

I've been trying to get a handle on web server performance on GFS mounted 
storage vs none. Since the other thread kind of got lost, I decided to start a 
new one. What I've found is interesting enough that I felt I should talk about 
it since I'm surely not the only one using Joomla, in this case.

This test is without GFS mounted as the root of the web server. The root of 
the site only has an index.html file with little in it;

#ab -k -n 100 -c 100 http://192.168.1.92/

Time taken for tests:   0.279518 seconds
Requests per second:    357.76 [#/sec] (mean)
Time per request:       279.518 [ms] (mean)
Time per request:       2.795 [ms] (mean, across all concurrent requests)
Transfer rate:          146.68 [Kbytes/sec] received

Same test with GFS mounted as the root of the web server. The root of the site 
only has an index.html file with little in it;

# ab -k -n 100 -c 100 http://192.168.1.92/

Time taken for tests:   0.162151 seconds
Requests per second:    616.71 [#/sec] (mean)
Time per request:       162.151 [ms] (mean)
Time per request:       1.622 [ms] (mean, across all concurrent requests)
Transfer rate:          160.34 [Kbytes/sec] received

Similar right? Now, let's try the same test but this time, we add a full bore 
application, a Joomla site in this case at the root of the web server;

#ab -k -n 100 -c 100 http://192.168.1.92/

Time taken for tests:   33.583784 seconds
Requests per second:    2.98 [#/sec] (mean)
Time per request:       33583.782 [ms] (mean)
Time per request:       335.838 [ms] (mean, across all concurrent requests)
Transfer rate:          27.42 [Kbytes/sec] received

Quite the difference and little to do with GFS from what I can tell. And, this 
is what I am trying to confirm, and am asking from the community. Is there any 
fine tuning needed for GFS and the cluster itself as well as what ever I will 
do with the cluster later?

In another thread, I was told that GFS would hurt performance and my thought 
was that well, yes, it would take up some of the servers resources but there 
should be plenty left over to handle web serving or what ever else the server 
needs to serve up. 

I've tested this in various ways today, from external connections, internal, 
various httpd.conf settings, it's always the same. While some of the 
httpd.conf settings have some effects, the biggest one is always what 
application is being run on the server. In this case, Joomla seems to be 
insanely resource intensive. 

Are there any thoughts on this so that I can know where I need to spend my 
time now. Should I worry about GFS and the cluster itself or move on and start 
trying to figure out how to get Joomla to run more effectively?

Mike