I've got performance issues on a server I've just set up, it's a Fujitsu TX200 S6 quad core running 4 win servers (SQL server, Terminal server, Exchange and AD) over vmware. It came with a pre-installed LSI MegaRaid card (haven't managed to discern which model) with 512MB RAM, due to HDD availability issues I ended up with 3 x Seagate Barracuda XT 2TB 3.5 SATA Internal Hard Drive (64MB cache) in a raid 5 array.

We're having intermittent performance issues over the servers but according to the VM console RAM & CPU utilisation is fine, the only thing that's looking poor is write latency. Have spoken to Fujitsu who say that we should try enabling write cache on the controller, I've bought the BBU to protect the data and will be installing it on Sunday.

Am I looking in the right place? Does enabling write cache make much difference? Should I have hung on for SAS disks?

In the previous setup the SQL & Exchange machines were on a single core Dell (5 yrs old?) and the AD & terminal server on a dual core Fujitsu TX100 S5 (3 yrs old?). All on much less total RAM, and performance was acceptable, I expected performance to be better.

Any help appreciated.