The load on my server is very high, even though there doesn't seem to be much disk activity and the CPU is idle. Using sar, I can see the run queue is getting full, but is there any way to see what's in the run queue?
I have a Python script running on my server as a FastCGI using Apache2 and mod_fcgid. I let it spawn up to five processes. But I soon get messages like these in the Apache logs:
[Wed Sep 02 23:16:34 2009] [warn] (103)Software caused connection abort: mod_fcgid: ap_pass_brigade failed in handle_request function
[Wed Sep 02 23:16:35 2009] [warn] (103)Software caused connection abort: mod_fcgid: ap_pass_brigade failed in handle_request function
and then Apache doesn't seem to recognize that all its processes are dead (I have a max of 5 backends) and refuses to spawn new ones:
[Wed Sep 02 23:26:16 2009] [notice] mod_fcgid: /var/www/hacks.og.theinfo.org/picker.fcgi total process count 5 >= 5, skip the spawn request
[Wed Sep 02 23:26:17 2009] [notice] mod_fcgid: /var/www/hacks.og.theinfo.org/picker.fcgi total process count 5 >= 5, skip the spawn request
at which point it refuses to respond to requests from the outside world. This doesn't seem to happen with my other FastCGIs, which all use the same Apache config:
<IfModule mod_fcgid.c>
AddHandler fcgid-script .fcgi
IPCConnectTimeout 20
MaxProcessCount 5
DefaultMaxClassProcessCount 2
DefaultMinClassProcessCount 1
</IfModule>
Any idea what causes it?