I've setup a radiant 0.9 (edge) instance running on a 256MB Slicehost slice (running Ubuntu Hardy) and am noticing some significant performance issues. Wonder if anyone might shed some light.
The http sever is litespeed. Database is mysql. Monitoring with "top" I see lshttpd (litespeed) using 0.7-1% of memory, mysqld using 2-3%. Neither process uses any negligible cpu. "free -m" shows numbers like: -/+ buffers/cache: 160 95 Swap: 511 90 421 On the other hand, there are usually 2-4 ruby processes each using about 20-30% memory, and peaking at about 25% cpu usage. Machine load average ranges from .01 to .9. Under these circumstances, I'm seeing these kinds of numbers in the production.log when accessing pages on the site: Completed in 1445ms (DB: 127) ... Completed in 1838ms (DB: 317) ... Completed in 4037ms (DB: 998) ... Completed in 4865ms (DB: 488) ... These are "good" numbers; sometimes the total completed is in the 20000-40000ms range! I don't understand where the bottleneck is. The db times are consistently less than 1000ms and usually under 500ms. What's worse though is over time, no idea why, the ruby processes will start to runaway and I'll end up with 8-10 of them each vying for 20-30% of memory. Machine load avg spikes up to 14 and the system is essentially unusable and needs a reboot. I'm considering bumping the slice memory up to 512MB, but am concerned that all it will do is delay the inevitable runaway ruby processes. Anyone have any idea what might be going on here? Anything I can do to pinpoint the cause of the problem? Any and all help greatly appreciated. -- marshal