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I moved tow drives which where mounted in a raid1 to another to a new system to be mounted there. One drive was detected instantly, the other one had issues with the super blocks. After reading Kevin Deldycke's Blog, I decided to mdadm --zero-superblock /dev/sdb and .../sdeto the both drives. I could then reassemble the tow drives mdadm --create /dev/md0 --verbose --level=1 --raid-devices=2 /dev/sde /dev/sdb. As shown by cat /proc/mdstat:

$ cat /proc/mdstat
Personalities : [raid1] 
md0 : active raid1 sde[0] sdb[1]
      3906886464 blocks super 1.2 [2/2] [UU]
      [============>........]  resync = 62.7% (2453058112/3906886464) finish=198.9min speed=121761K/sec
      bitmap: 12/30 pages [48KB], 65536KB chunk

unused devices: <none>

But I now I can not mount /dev/md0

$ sudo mount /dev/md0 /mnt/nas/
mount: /mnt/nas: wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error.
       dmesg(1) may have more information after failed mount system call.

I have tried:

sudo fsck -CV /dev/md0
sudo e2fsck -b 8193 /dev/md0

the later one with different sizes to no avail.

Is there a way to remount the drives or is my data lost? Thanks for your help.

My System: fedora 5.19.12-200.fc36.x86_64

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  • Its likely you data owerwritten by syncing. Also its totally wrong solution for your problem. Now you may try scan md0 to find fs remnants. cgsecurity.org/wiki/TestDisk_Step_By_Step Commented Oct 5, 2022 at 17:04
  • 1
    The blog you referenced also said zeroing the superblocks "was the stupidest idea of the week". Commented Oct 5, 2022 at 17:19
  • For future: (re)creating something over old one destroy old one in most cases (100% for metadata) Commented Oct 5, 2022 at 17:31
  • In your case you should be just remove "failed" drive from raid array an readd it (or new one) back so it syncing with healthy drive. Commented Oct 5, 2022 at 17:36
  • Also read raid.wiki.kernel.org/index.php/Initial_Array_Creation Commented Oct 5, 2022 at 17:44

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