[TriLUG] mdadm: no devices found for /dev/md0
tbryan at python.net
Thu Nov 30 07:57:53 EST 2006
For the archives...
On Wednesday 29 November 2006 19:51, T. Bryan wrote:
> Some progress! I think that the problem may be that I once created a RAID
> on these devices incorrectly. I later reconfigured my RAID, but I think
> that the boot sequence is now detecting the old RAID set. I could use some
> help from another RAID user out there.
> If you have a RAID1 between /dev/hda1 and /dev/hdc1, for example, what do
> the following 4 commands return?
> Anyway, I think that I might just need to run
> mdadm --zero-superblock /dev/hde
> mdadm --zero-superblock /dev/hdg
> and reboot. I just don't want to do that until I'm a little more certain
> that the md superblock isn't supposed to be there.
I decided to give it a try without a confirmation that this guess was what was
really happening. As a German friend used to say, "Mut zur Luecke!" (Courage
through the gap.)
Zeroing the superblocks fixed my problem and didn't appear to break anything
I think that after my recent upgrades, udev was seeing the md superblock on
the /dev/hde and /dev/hdg devices and not even creating the /dev/hde1
and /dev/hdg1 devices. Now that there are no longer obsolete md superblocks
on /dev/hde and /dev/hdg, udev is making /dev/hde1 and /dev/hdg1 available
after boot, and mdadm is able to bring up /dev/md0 as a RAID1 across those
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