[TriLUG] mdadm: no devices found for /dev/md0
tbryan at python.net
Wed Nov 29 19:51:27 EST 2006
On Tuesday 28 November 2006 08:53, T. Bryan wrote:
> After recent upgrades, my RAID1 device does not seem to be coming up during
> the boot process any more.
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?
mdadm --examine /dev/hda | grep UUID
mdadm --examine /dev/hda1 | grep UUID
mdadm --examine /dev/hdc | grep UUID
mdadm --examine /dev/hdc1 | grep UUID
I'm hoping that the command on /dev/hda and /dev/hdc will tell you that there
is no md superblock. :)
On my machine, I should have a RAID1 between /dev/hde1 and /dev/hdg1, but I'm
showing an md superblock on /dev/hde and /dev/hdg, too. I don't think that's
normal, but I'd like to confirm that with anyone else who's running a RAID.
I'll have to look at my notes, but I think that I once tried to create a RAID
directly on the unpartitioned devices. When I finally set up the RAID, I
partitioned the devices and created the RAID across the partitions, not the
raw devices. But now, when my system boots up, it's bringing up the RAID on
/dev/hde and /dev/hdg and not on /dev/hde1 and /dev/hdg1. Worse, it looks
like udev isn't recognizing /dev/hde1 and /dev/hdg1 because it has decided
that /dev/hde and /dev/hdg are completely dedicated to a RAID.
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.
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