Hi I have a big problem with all my blogs on the server, the CPU usage keeps going over the top, and I already upgraded twice but in vain (VPS on servint) I have about 30 blogs hosted on the account, all use wordpress, and all employ the w3 total cache plugin, the busiest blog gets about 3000 visitors a day, and there are only 2-3 blogs like that, the rest are less busy but are auto blogs, using feedwordpress and auto posting scripts. again -- all cached. How can I further reduce the CPU usage, without going into the high end upgrades? I did all the basic things like removing a lot of dynamic elements, timthumb, replacing queries with hard coded html wherever possible - nothing helps. Server admins say I need to upgrade again, but then again, what else will they advice. Any ideas what can be done? Thanks in advance!
You need to enable slow query log in MySQL to find out the slow queries and fix them if needed. I found this URL on DP on wordpress performance (http://blog.mellowhost.com/reducing-cpu-usage-for-wordpress-users.html). See if this post related to wp-cron.php is helpful to you.
What are the specs on the server? Do you have full ssh access? Are you using default MyISAM tables for the WP databases? What are your database configuration parameters? I would start with a good wp-cache plugin which have suggested is already done. Next I would make sure to use APC or another opcode caching mechanism. APC is by far the easiest to get running. Make sure your images are browser cached by using an expires header. You can set this in htaccess for css, javascript, images, etc.. If you have a lot of javascript and css, make sure they are reduced in size.