RRD graphing slowness

[r00ler]

I've been messing with this for a couple days now and while I've seen a few older topics on the subject I haven't seen a resolution to the issue that is suitable for me.

First of all, this is a Fedora 12 system, Apache 2.2.15, PHP 5.3.3, RRD 1.3.8. running in a VM with 2gb RAM and 8 x 2.33ghz CPUs.

When loading a page in my graph tree that has many graphs on it, the graphs take an awful long time to come up. Running the rrdtool command directly seems to complete nearly instantaneously. I've also made a small bash script to generate 1000 graphs at a time for reference while troubleshooting. Right now I'm seeing the following numbers: 2:32 to write 1000 graphs to filesystem, 1:55 to tmpfs. An entirely unscientific test of loading a cacti page with 100 graphs and watching the clock gives 27 seconds for completion. Some basic math puts this multi-threaded web-page load at taking nearly twice as long to generate the equivalent number of graphs that my crappy single-threaded bash script can do.

There are threads on these forums stating that it appears Apache+PHP 5.3 is the culprit, which is nice except that reverting to 5.2 is an annoying solution. While I am comfortable doing this change, I am not the only one supporting this server and the others on my team have much less Linux exposure than I do, so I'd like to stick with the available RPMs if at all possible.

So, where does that leave me? What info can I provide to help troubleshoot this issue?

Thanks in advance for any help.

[blkcamarozr28]

Apache is slow when rendering lots of graphs. Change your webserver to Lighttpd it makes a world of a difference.

[r00ler]

Switching to Lighttpd is consistently giving me ~35 second page render times for 100 graphs, which is significantly slower than the consistent ~27 second render times Apache was giving. Still, neither are particularly awe-inspiring and I'd like to speed them up if at all possible. Any more suggestions?

[gandalf]

It has been reported, that rrdtool 1.3.8 under some circumstances is quite slow when running under php/Apache. We did not yet narrow this down. Users reported to e.g. downgrade to rrdtool 1.2.x which solved the problem.
It is known, that a plain php script does NOT cause the issue; only when running under Apache it will slow down (not verified).
R.