I'm encountering unfamiliar Apache symptoms and I'm curious if anyone here knows how to diagnose them. I've got a pair of app servers running mod_python and Apache, recently upgraded to Django 1.2.3. They plug into a db server that runs PostGIS and memcached.
Here's what I'm seeing in 'top':
The app servers httpd processes climb to the low 20s.
The app servers CPU's %wa, which, in the past, had been almost always near zero, starts dancing around %50.
I restart apache, the problems go away. It's only recurred once so far, but I'm worried it might, and I'm curious to get to the bottom of it. Anyone seen this before? Know the smart way to deal with it? I'm planning on trying to closely the examine io operations if it crops again, but don't have a good grip on it.