I've a RAID1 device created with mdadm in liveuUSB mode. When I rebooted I'm front of Grub Rescue interface. So I restarted in liveUSB system and I assembled my RAID1 like :

mdadm --assemble /dev/md0 /dev/sda1 /dev/sdb1 
mdadm: /dev/md0 has been started with 2 drives.

And I checked :

    ~# cat /proc/mdstat                             Personalities : [raid1] 
    md0 : active raid1 sda1[0] sdb1[1]
          479863808 blocks super 1.2 [2/2] [UU]
          bitmap: 0/4 pages [0KB], 65536KB chunk

    unused devices: <none>

I tried to mount /dev/md0 on a mount directory for reinstall GRUB and I've got this error message :

       ~# mount -t ext4 /dev/md0 tmp
       mount: wrong fs type, bad option, bad superblock on /dev/md0,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

I checked the syslog :

:~#  dmesg | tail                                                                                                    
[ 1744.109048] EXT4-fs (md0): VFS: Can't find ext4 filesystem     

I suppose I can not boot the system with RAID1 configured as the grub doesn't reconize the md0 files system. So for booting the system, I've to do fsck.ext4 -f -y on each devices and the Grub can recognize the file system of /dev/sda1, but I can not assemble the booth devices as RAID1 may fsck.ext4 removed the superblock or /dev/sda1 is busy.

How I should to do for get an issue?

  • your /dev/md0 is a device, you should make the filesystem on it to mount it, in other words you need a step of mkfs.ext4 /dev/md0. after you can mount it. – Hamza Jabbour Mar 10 '17 at 19:38
  • Thanks but this action will erase everything on my disk, won't it? – dubis Mar 13 '17 at 7:21

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