I have an OSQA (python / django q&a application) installation serving 8 different sites. The sites are all in development, receiving minimal traffic. The server is a virtual private server with 512 mb of ram.
Apache is only serving dynamic pages with mod_wsgi behind Nginx. I can't stop Apache consuming more and more memory with each request until the server chokes.
I experimented with the configuration parameters without much luck to minimize the memory footprint. With the following mpm_prefork parameters in apache2.conf:
StartServers 2
MinSpareServers 1
MaxSpareServers 4
MaxClients 4
MaxRequestsPerChild 100
2 apache processes start using 4 mb and after the first request there are 4 processes with each nearly 50 mb and with each new request those 4 processes climb steadily up to nearly 200 mb each.
I feel like there is something wrong going on. Any suggestions are greatly appreciated.
KeepAlive Off
MaxSpareThreads 3
MinSpareThreads 1
ServerLimit 3
SetEnvIf X-Forwarded-SSL on HTTPS=1
ThreadsPerChild 2
WSGIDaemonProcess osqaWSGI processes=2 python-path=/web/osqa_server:/web/osqa_server/lib/python2.6 threads=1 maximum-requests=550
WSGIProcessGroup osqaWSGI
Ran httperf against this with 10,000 concurrent hits and it was still standing.