Linux

In addition the advice from csorhand and looking at your processes it appears that you are using a LAMP configuration, so there are several things to take into account here (I am assuming the php part).

1. Examine your content, if you are serving pages that contain mixed content such as images and javascript along with dynamic php content, you might benefit from adding expiry to the static content, if client need to download less that will reduce some of your load.

Code:

        <IfModule mod_expires.c>
                ExpiresActive On
                <FilesMatch "\.(css|js|gif|jpg|jpeg|png|swf)$">
                        ExpiresDefault A2592000
                        Header Append Cache-Control "public"
                </FilesMatch>
        </IfModule>

2. Install a php cache such as xcache, eAccelerator or APC.

3. Look at this thread https://www.unix.com/web-programming-...primer-sh.html and use the tools linked to check your mysql configuration. I believe it is actually your communication with MySQL which is causing you the most problems.

4. Ensure that you have dns lookups turned off in apache:

Code:

HostnameLookups Off

Also check for "bad" pages that have nasty queries. We has on module on this site that put millions of rows in one db table, and tried to query that table every time specific pages were loaded. The server was running flat out for a few days until I managed to spot the strange behavior and truncated the table. The load went down instantly to a normal level.