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Minimum Spare Servers 8
Maximum Spare Servers 32
Max Clients 1500
Max Requests Per Child 0
Start Servers 8
Server Limit 2000
Keep-Alive Timeout 15
Max Keep-Alive Requests 256

Other options:

–addition of memcache
–recompiling Apache to run as PreFork opposed to MPM Worker Event

Check for Prefork or Worker

# [root@austin ~]# /usr/sbin/httpd -V | grep MPM
# Server MPM:     Prefork
# -D APACHE_MPM_DIR="server/mpm/prefork"

Links:
http://kb.sp.parallels.com/en/113007
http://codebucket.co.in/apache-prefork-or-worker/
–Reduced some of the limits in the apache config. Many things that should be in the hundreds were set in the thousands.
–KeepAlive on was simply adding too large of a load to the server.


Timeout
Timeout 300

Usually this value doesn’t require editing and a default of 300 is sufficient. Lowering the ‘Timeout’ value will cause a long running script to terminate earlier than expected.

On virtualized servers like VPS servers, lowering this value to 100 can help improve performance.


KeepAlive
KeepAlive On

This setting should be “On” unless the server is getting requests from hundreds of IPs at once.

High volume and/or load balanced servers should have this setting disabled (Off) to increase connection throughput.


MaxKeepAliveRequests
MaxKeepAliveRequests 100

This setting limits the number of requests allowed per persistent connection when KeepAlive is on. If it is set to 0, unlimited requests will be allowed.

It is recommended to keep this value at 100 for virtualized accounts like VPS accounts. On dedicated servers it is recommended that this value be modified to 150.


KeepAliveTimeout
KeepAliveTimeout 15

The number of seconds Apache will wait for another request before closing the connection. Setting this to a high value may cause performance problems in heavily loaded servers. The higher the timeout, the more server processes will be kept occupied waiting on connections with idle clients.

It is recommended that this value be lowered to 5 on all servers.


MinSpareServers
MinSpareServers 5

This directive sets the desired minimum number of idle child server processes. An idle process is one which is not handling a request. If there are fewer spareservers idle then specified by this value, then the parent process creates new children at a maximum rate of 1 per second. Setting this parameter to a large number is almost always a bad idea.

Others Suggestions:


Virtualized server, ie VPS 5
Dedicated server with 1-2GB RAM 10
Dedicated server with 2-4GB RAM 20
Dedicated server with 4+ GB RAM 25
MaxSpareServers
MaxSpareServers 10

The MaxSpareServers directive sets the desired maximum number of idle child server processes. An idle process is one which is not handling a request. If there are more than MaxSpareServers idle, then the parent process will kill off the excess processes.

The MaxSpareServers value should be set as double the value that is set in MinSpareServers.


StartServers
StartServers 5

This directivesets the number of child server processes created on startup. This value should mirror what is set in MinSpareServers.


MaxClients
MaxClients 150

This directive sets the limit on the number of simultaneous requests that will be served. Any connection attempts over the specified limit will be queued. Once a process is freed at the end of a different request, the queued connection will then be served.

For virtualized servers such as VPS accounts, it is recommended to keep this value at 150. For all dedicated servers the recommended value for this setting is 250.


MaxRequestsPerChild
MaxRequestsPerChild 0

This directive sets the limit on the number of requests that an individual child server process will handle. After the number of requests reaches the value specified, the child process will die. When this value is set at 0, then the process will never expire.

Other adjustments:


Virtualized server, ie VPS 300
Dedicated server with 1-4GB RAM 500
Dedicated server with 4+GB RAM 1000

Other resources:
http://httpd.apache.org/docs/2.2/misc/perf-tuning.html
https://www.howtoforge.com/configuring_apache_for_maximum_performance
http://stackoverflow.com/questions/8902103/is-there-an-apache-tuner-script-like-mysqltuner-pl