We have a Dell PowerEdge 2500 server with 4 18GB Hard Drives on the Raid controller.  We have room to install 2 more drives because the tape backup is also installed.  Now we are trying to gain more storage options with minimal work as far as messing too much with the server.  I was wondering if we installed two new hard drives on the system, will there be anything required to do or will it automatically recognize them and start using them for storage?

Forgive me, I am not used to the Raid system.  I usually work on servers with one hard drive, so I may sound a bit idiotic.