Noob Centos Admin wrote: > Hi, > >> If you want a fast database forget about file system caching, >> use Direct I/O and put your memory to better use - application >> level caching. > > The web application is written in PHP and runs off MySQL and/or > Postgresql. So I don't think I can access the raw disk data directly, > nor do I think it would be safe since that bypasses the DBMS's checks. Which is it? mysql or postgresql or both? Have you actually determined that i/o is in fact the bottleneck? Is the webapp maintaining persistent connections to mysql or is it continually connecting and disconnecting? mysql sucks big time if you have a good few hundred connections being setup and torn down all the time. Are complicated relationships being stored in postgresql and not in mysql? I do not know how things are now but mysql has a history of only being good for simple selects.