We have a machine that’s a distro mirror – a *lot* of data, not just CentOS. We had the data on /dev/sdc. I added another drive, /dev/sdd, and created that as /dev/md4, with –missing, made an ext4 filesystem on it, and rsync’d everything from /dev/sdc.
Note that we did this on *raw*, unpartitioned drives (not my idea). I then umounted /dev/sdc, and mounted /dev/md4, and it looked fine; I added
/dev/sdc to /dev/md4, and it started rebuilding.
Then I was told to reboot it, right after the rebuild started. I don’t know if that was the problem. At any rate, it came back up… and /dev/sdc is on as /dev/md127, and no /dev/md4, nothing in /etc/mdadm.conf, and, oh, yes, mdadm -A /dev/md4 /dev/sdd mdadm: Cannot assemble mbr metadata on /dev/sdd mdadm: /dev/sdd has no superblock – assembly aborted
Oh, and mdadm -E /dev/sdd
MBR Magic : aa55
Partition : 4294967295 sectors at 1 (type ee)
ee? A quick google says that indicates a legacy MBR, followed by an EFI….
I *REALLY* don’t want to loose all that data. Any ideas?