Mark Rogers wrote:
Ah, trivial then! Actually does sound fairly straightforward, and at this point I'll have two 500GB drives with full backups anyway!
If only!
It turns out that I had 4 drives as RAID5, not 2-off RAID1 pairs.
Hopefully this will still work out OK, though. I've got 4 new 1TB drives, and I'm replacing them one at a time, partitioning them as a single partition spanning the whole disk (filesystem type "fd"), then adding them to the array with mdadm -a /dev/md0 /dev/sda1 (etc).
Thus far I am 10 mins into the process, with /proc/mdstat suggesting I need about 3hrs for this drive alone, so I'm looking at somewhere through tomorrow before I complete this task.
PS: To recall a recent thread, these new drives came from TekHeads and were sensibly packaged!