Re: Requesting assistance recovering RAID-5 array

Daniel Jones
2020-04-03T18:29:56Z

Hello again,

> Don't do the --add operation until you've copied anything critical in the array to external backups (while running with 3 of 4).

Everything from the array has been backed up elsewhere.

Up until now the only writes intentionally done to the physical drives
have been the new partition tables. Everything else has been through
the overlay.

Now I think I'm ready to run a --create as follows on the physical drives:
mdadm --create /dev/md0 --assume-clean --data-offset=129536 --level=5
--chunk=512K --raid-devices=4 missing /dev/sdc1 /dev/sdd1 /dev/sde1

After that I'd try to re-add the rejected drive?
mdadm --manage /dev/md0 --add /dev/sdb1

Part of me wonders about just rebuilding the whole thing and then
copying the data back, but I don't know that would be any better then
this path.

Thanks,
DJ