I was in the market recently to deploy few dedicated servers for a solution and one of the servers happened to require large amounts of storage (in the range of a few terabytes). After scoping out a bit, I figured my choices were to deploy a single storage server (with a large number of disks, typically SATA since they give higher capacity) or buy capacity on a SAN. The problem with putting all storage on a single server was its inscalability as the system would grow. A SAN on the other hand required expensive set up and higher fees. It was the most flexible option though. Eventually I decided to use neither. The solution was to modify our software to utilize an array or storage servers in the network where each server would have a few hundred GBs of disk space on RAID drives. We found this to be cheaper and readily deployable by our partners who had lots of unused servers they bought in 2007 or prior years. I think this form of storage is similar to Storage grids or clouds using commonly available servers (with no special drives or availability mods). We also could distribute these servers all over the internet in various borrowed data centers which is quite cool.