I currently have a RAID level 1 of 2 500 GB HDs. The RAID is managed by server 1 and the drives are in 2 different servers.
The RAID works great once I get it setup, however, at random times the connection seems to get dropped and mdadm marks it as faulty and even though I use nbd-client with the -persist option; mdadm refuses to see the drive as good. The only way to get this disconnect drive back into the RAID array is to:
mdadm -r /dev/md0 /dev/nbd1
mdadm -a /dev/md0 /dev/nbd1
My problem with this is that it causes a FULL RESYNC of 500GB over the network.
I have 2 questions to this problem:
Is there a way to tell mdadm not to complete a full resync because it does complete a resync before it disconnects so I can't see a good reason for it to perform a FULL resync?
Would I be better off with rsync because all I need is just a backup copy of whatever data I write/delete? I suggest this because rsync, supposedly, only transfers the delta (or changed) data instead of what mdadm seems to be doing.