My NAS 540 Lost two drives while I was on vacation. There are 4 drives.

Rhoisy

two have changed states to hot swapable. I replaced the two that were bad. It was a raid 5. Now I can't get anything to work. The two Hot Swapable will not do anything, the new one will not do anything, except I can group them together, but I cannot group the Hot Swapable to the others. I have a backup of what was there on a backup drive. So how do I get all four drives into a raid configuration and then get the backup reinstalled.

Rhoisy

I figure this was asked before, so I suspect it is in the FAQ. can't find it, so can someone point me in the right direction?

Mijzelf

Well, it's good that you have a backup. It might be possible to rescue the array, but restarting is simpler.

Your problem now is that raid5 can handle the loss of one single drive. You lost two (/why/ you lost two is a different question), and so the array cannot be automatically repaired. If you didn't have a backup it might have been possible to re-add the dropped disks using some low-level commands, but that's not needed now.

You can simply delete the volume, and create a new one. But before you do, have a look at the SMART values of the disks, there might be a reason why the disks were dropped.