OK I just noticed something... On Fri, Mar 8, 2019 at 12:56 AM <no_spam@xxxxxxxxxxxx> wrote: This is from your blkid ID command on the NAS: > /dev/md4: LABEL="2017.05.25-01:26:55 v15101" > UUID="f4bc4bd1-af0d-4d54-9b05-6a719ddec086" > UUID_SUB="e40c544c-3d7d-4e01-93af-a5b70985d4f1" TYPE="btrfs" This is a partial hexdump from the safepathtofile-sda6 file you made of the "missing" drive that escaped being zero'd 00030020 f4 bc 4b d1 af 0d 4d 54 9b 05 6a 71 9d de c0 86 |..K...MT..jq....| 00030030 00 00 01 00 00 00 00 00 01 00 00 00 00 00 00 00 |................| 00030040 5f 42 48 52 66 53 5f 4d 5a 66 18 00 00 00 00 00 |_BHRfS_MZf......| The FS UUID's match. So we actually have a single Btrfs volume that's spanning /dev/md2 and /dev/md3 via LVM, and /dev/md4. That's curious. -- Chris Murphy
