After the "--create missing /dev/sdc1 /dev/sdd1 /dev/sde1" and the fsck, is "mdadm --manage /dev/md0 --add /dev/sdb" the correct syntax for attempting to add? -DJ On Fri, Apr 3, 2020 at 12:34 PM Phil Turmel <philip@xxxxxxxxxx> wrote: > > On 4/3/20 2:29 PM, Daniel Jones wrote: > > 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. > > Sounds like a risk-free decision. mdadm --create --assume-clean > followed by a proper fsck will be lots faster than mdadm --create, mkfs, > and copying. > > I'd go fast. > > Phil
