Optimize Apache For Heavy Traffic

The default Apache settings that cPanel sets upon install are definitely something that can be improved on. With a few small tweaks, the efficiency with which Apache runs with can be greatly improved.

To start with, lets go ahead and open the Apache configuration file:

vim /usr/local/apache/conf/httpd.conf

This list is a composite of the settings we will be reviewing from fresh install on a cPanel server:

Timeout 300

KeepAlive On

MaxKeepAliveRequests 100

KeepAliveTimeout 15

MinSpareServers 5

MaxSpareServers 10

StartServers 5

MaxClients 150

MaxRequestsPerChild 0

Please note, the settings that we will review in this article are by no means a complete list

of tweakable options in the Apache configuration file. The settings we will be focusing on are

the ones that control how Apache handles webpage requests.


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 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 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 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 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.

Ajusting the value for this setting to the following:

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 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 5

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


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 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.

Some Recommended Values

Virtualized server, ie VPS 300

Dedicated server with 1-4GB RAM 500

Dedicated server with 4+GB RAM 1000

How to set up DM-RAID drives in a rescue environment

After beating my head against a wall for a significant period of time because of a software RAID issue, I figured out how to set it up. Because it was so difficult I figure I would pass the savings on to you. OK here’s what we need to do. First thing is we need to figure out what our arrays are going to be made from. This is simply done with fdisk. After that we would vi /etc/mdamd.conf and add a line like this one:

DEVICE /dev/sdaN /dev/sdbN /dev/sdcN

and so on where sda/b/cN are the partitions our RAIDs are made of. Don’t worry about which is which mdadm will take care of that with the uuids.

Run this next:

mdadm –examine –brief –scan –config=partitions >> /etc/mdadm.conf

and it will put the information for the array into the config file. After this all we need to do is run:

mdadm -A /dev/mdN

for each device we want to set up. Mount as normal. Have a lot of fun