I recently set up a raid 1 array. Both / and /boot are on md0 (sda, sdb).

everything was working when it was in degraded mode before I synced the two disks together. It was booting from grub2 on sda into md0 which was only on sdb.

Grub2 was installed on both sda and sdb

Now that I have synced the two drives the machine wont boot. It goes straight into a grub rescue prompt.

if i do a ls it does not list my raid drive like it was doing before and it wont let me manually boot from hd0 etc presumably because the sync has overwritten it?

I tried booting into a rescue cd but i can't mount to the partition because it is of type linux-raid.
I can't re-install grub because i can't mount to the drive

I don't really know where to go from here.

I am running Mint 13

Any advice would be appreciated!

  • I forgot to add that when in the grub recovery pronpt, if i try to run insmod mdraid1x or linux or normal it fails with file not found. The only module i could find that would run was ext2
    – Karl
    Commented Sep 7, 2012 at 13:48

1 Answer 1


I know this is an old question, but somebody else might be searching for the same thing, so I figured I'd answer it, anyway.

When booting from the rescue CD, you first have to assemble the md raid device, before you mount it:

mdadm --assemble /dev/md0 /dev/first-device-of-raid1 /dev/second-device-of-raid1

Then you're going to mount the md0 device, rather than the individual partition:

mount -o ro /dev/md0 /media/mountpoint/

That will mount it read-only, of course, but that's a good idea until you know that everything's working properly, so you don't end up completely borking an already potentially iffy filesystem. Once you know the filesystem is fine, your files are accessible, etc, then you can try reinstalling grub, and the command line for that has enough potential variables that I'm going to leave it to some indepth man page reading.

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