I have a friend who has two servers, a Dell 1800 and an HP 350 ML G5, both have SAS drive arrays. The Dell is a 3.5" and the HP is a 2.5".

They currently only have 3 drives in each array. We want to add additional drives, but they do not appear to have caddies, just "fake" covers. I haven't been able to take a good look at them, so I'm not sure what I need to do here. Are the "sockets" just there, and I can buy additional caddies and just stick them in? Or do I have to buy some kind of caddy adapter?

Also, i'm thinking of just going 2.5" in the new server, so is there a 2.5" adapter caddy that will fit in the 3.5" chassis for the Dell, so I can use 2.5" drives in the 3.5" chassis?

Can I buy 6GB/s drives and add them to the 3GB/s controller? The reason is that we're going to replace both computers in a year or so, and we want to bring the drives with. So rather than buy 3GB/s drives, we just want to buy 6GB/s drives so they can be used in the new server.