So I've been having increasing performance issues in the past few months as one of the websites on my dedicated server has grown in popularity. The large database is 11GB. There are times when the server is going absolutely bat**** crazy with loads in the 20's, yet running "top" usually shows that the CPU is mostly idle. I fire up the list of MySQL Processes, and it's rare that there is one definitive query that is holding up the show. I am running a cPanel/WHM CENTOS setup with MySQL 5.0.x (Yes it's ancient, and an upgrade is imminent), PHP 5.3, and Apache 2.2 on a dedicated Xeon quad core box with 4GB of RAM and 250GB hard drive. So here's the issue. I contacted my host and here's the relevant passages from some of the ticket responses they've been sending me. I indicated that I intend to do full server backups very soon, and then do a MySQL 5.0 -> 5.1 -> 5.5 upgrade, but first wanted their advice on any other problems they saw before I do so... and later Also, to the idea of me upgrading the server to MySQL 5.5 with the automated cPanel scripts, they had this: So has anyone heard of this concept that a MySQL can be optimized for LARGE databases or SMALL databases, but cannot effectively serve both? I could understand if the server I have is inadequate. I cannot understand that I would need two weaker boxes rather than one strong box. Shrinking the database is, of course, not an option (strangest suggestion I've ever heard). What would you do at this point?