hmmm... normaly the old boxes RAID5 combo's are no different from a new RAID5, I have an old RAID5 server running with hotplug 2.1 GB SCSI disks, this thing sounds like a jet too You can hear every disk spinning up to its speed when you switch it on.

The config is simple RAID5 with 5 disks resulting in 8GB usefull space. Every disks hold data so that the array can rebuild when there is a failure of one disk.
Are you sure you placed all the disks in the same array?

The best way to work is to clear the RAID config and clear the data on the disks (if you don't need them) and start a new clear raid array configuration from the cd or disk that manages that server (like compaq gave out with their proliant servers) It's very straightforward to config a raid with those tools. I bet IBM has a similar system, or probably you need to press a F key to enter the RAID config info.