httpd stuff

list compiled modules
 $ httpd -l
 
 Estimate memory usage per apache process
 $ ps -lyC httpd --sort:rss | awk '{sum+=$8; ++n} END {print "Tot="sum"("n")";print "Avg="sum"/"n"="sum/n/1024"MB"}'
 
 The max value for MaxClients/MaxServers should be set to 80% of memory consumption 
 (i.e. mem per httpd process divided by 80% system memory.)
 
 Or, for another version from https://gist.github.com/tbjers/4496984 with slight modifications, try this,
 
 ps -ylC httpd --sort:rss | awk '{ s += $8; } END { print "Average Size:", s/(NR-1)/1024, "MB,\nProcesses:   ", NR-1, "\nTotal usage: ", (s/(NR-1)/1024)*(NR-1), "MB, \nMax Servers: ", 6500/(s/(NR-1)/1024) }'
 

 
 
 List open files for apache
 sudo lsof | grep apache | grep <mount point file pattern>