How to optimize Apache configuration ?

Settings can be done in conf / httpd.conf

Timeout

• Amount of time Apache will wait to receive TCP packets and acknowledgements for a request
• Default : 300 (sufficient)
• Recommended for virtualized servers : 100  =>  improves performance

KeepAlive

• makes KeepAlive setting ON or OFF
• Possible settings : “KeepAlive off” or “KeepAlive on”

MaxKeepAliveRequests

• Max number of requests a single persistent connection will serve.
• used when KeepAlive is On
• Set to 0 = Unlimited requests
• Recommended for virtualized servers : 100  and Dedicated server : 150

KeepAliveTimeout

• Number of seconds Apache will wait for another request before closing the connection
• Recommended : 1 to 5 (Avoids wasting RAM while waiting for requests)
• Default : 15 (at higher side)
• High value = Performance issue in servers having heavy load

MinSpareServers

• Minimum number of idle child server processes (idle = not handling a request)
• Recommended :
• For virtualized server (Default) = 5
• For Dedicated server with 2 GB RAM = 10
• For Dedicated server with 4 GB RAM = 20
• For Dedicated server with 4+ GB RAM = 25

MaxSpareServers

• Max number of idle child server processes 
• Default : 10
• Recommended : Double of value set for MinSpareServers

StartServers

• Number of child server processes created on startup
• Default : 5
• Recommended : Same as value set for MinSpareServers

MaxClients

• Limit on the number of simultaneous requests that will be served
• Connection more than limit, will be in queue and wait for other processes to finish.
• Default : 150
• Recommended for virtualized server = 150 and dedicated server = 250

MaxRequestsPerChild

• Limit on the number of requests that an individual child server process will handle
• After number of requests reaches more than limit, child process will die.
• Default : 0 = process will never expire
• Recommended :
• For virtualized server = 300
• For Dedicated server with 1 to 4GB RAM = 500
• For Dedicated server with 4+ GB RAM = 1000