Ok so I have a 2 TB raid 1 setup that has three partitions:
- sdc1: linux
- sdc2: swap
- sdc3: LVM for data
However the LVM will no longer mount. So I thought that I would take the first drive, mount it in linux (ive done this b4), and reset the spare drive to copy the data.
Normally I can mount a single drive for data recovery using:
sudo su apt-get install mdadm lvm2 mdadm --assemble --scan modprobe dm-mod vgscan vgchange -ay c mount -o ro /dev/c/c /mnt
Unfortunately, vgscan doesnot recognize the data partition. It appears as though the superblock on the first drive's data partition was erased while syncing with the second. So now I cannot mount that partition and the second drive is stuck in spare mode.
Any ideas? Or a way to force mount the data partition just to copy the data?
knoppix@Microknoppix:~$ sudo su root@Microknoppix:/home/knoppix# apt-get install mdadm lvm2 Reading package lists... Done Building dependency tree Reading state information... Done lvm2 is already the newest version. mdadm is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 551 not upgraded. root@Microknoppix:/home/knoppix# mdadm --assemble --scan mdadm: /dev/md/1 has been started with 1 drive (out of 2). mdadm: /dev/md/0 has been started with 1 drive (out of 2). root@Microknoppix:/home/knoppix# modprobe dm-mod root@Microknoppix:/home/knoppix# vgscan Reading all physical volumes. This may take a while... No volume groups found root@Microknoppix:/home/knoppix# cat /proc/mdstat Personalities : [raid1] md0 : active raid1 sdc1 4193268 blocks super 1.2 [2/1] [U_] md1 : active raid1 sdc2 524276 blocks super 1.2 [2/1] [U_] unused devices: <none> root@Microknoppix:/home/knoppix# mdadm -v --assemble --auto=yes /dev/md2 /dev/sdc3 mdadm: looking for devices for /dev/md2 mdadm: no recogniseable superblock on /dev/sdc3 mdadm: /dev/sdc3 has no superblock - assembly aborted root@Microknoppix:/home/knoppix# dumpe2fs /dev/md0 | grep -i superblock dumpe2fs 1.42.4 (12-Jun-2012) Primary superblock at 0, Group descriptors at 1-1 Backup superblock at 32768, Group descriptors at 32769-32769 Backup superblock at 98304, Group descriptors at 98305-98305 Backup superblock at 163840, Group descriptors at 163841-163841 Backup superblock at 229376, Group descriptors at 229377-229377 Backup superblock at 294912, Group descriptors at 294913-294913 Backup superblock at 819200, Group descriptors at 819201-819201 Backup superblock at 884736, Group descriptors at 884737-884737 root@Microknoppix:/home/knoppix#
- I can read the super block from the spare drive.
- I was gonna try and restore the superblock from one of the backups, but i dont know how or if this would work.
- I also heard creating a new array (
mdadm --create) using the same parameters will not delete the data on the drive but i didnt want to risk it. Recommendations?