This may sound simple, but I cant find anything on Google for just adding a new disk.

This is a data disk, not boot or anything like that. I've got 6 disks in there, one of them almost dead, and I need to copy what I can from the dead one to the new one.

My problem is that when I go to format, I dont see the new disk listed. Similarly when I do df -k I still see a cdrom which I took out yesterday. Is there some way I can refresh to see whats currently in there? (Pref. without reboot as I dont think the old disk will make it)

Thanks in advance