Hi Troy,

On 12/13/2011 05:42 PM, Troy Telford wrote:

I have a RAID-6 array I'm having trouble with:

md2 : active raid6 sdl1[6] sdh1[0] sdm1[5] sdk1[3] sdj1[2] sdi1[1]
     1953535488 blocks level 6, 128k chunk, algorithm 2 [6/5] [UUUU_U]
     [>....................]  recovery =  0.0% (27164/488383872) finish=599.1min speed=13582K/sec

- When the system boots (or when I attempt to build the array), I get a message that /dev/sdl and /dev/sdl1 have the same superblock, and that I should zero one.
- So, I zero the superblock using 'mdadm --zero-superblock /dev/sdl (or /dev/sdl1; doesn't matter which I use).
- I then re-add the device to the array (and the RAID-6 array recovers, as above.)
- The next time I boot, I get the exact same error message.


- It doesn't seem to matter which (between the device or the partition) that I zero the superblock on.  I get the same error message at boot (when the drive is being assembled).
- Since it's redundant data anyway, I've tried dd'ing from /dev/zero over the drive, repartitioning the drive, and then adding the drive to the array. Same behavior.

- My mdadm.conf just has the array itself, and the array's UUID. It doesn't explicitly list devices.

So what am I missing? There's got to be a way I can get the array to assemble at boot, instead of having to manually --zero-superblock every time.

Let me guess:  You have version 0.90 superblock, and sdl1 covers the whole device?

Short term, change your mdadm.conf to only accept device names that end with a digit.  Like so:

DEVICE /dev/sd[a-z][1-9]

Then rebuild your initramfs to include the new mdadm.conf.

Long term, rebuild your array with v1.x metadata.

HTH,

Phil