Re: Linux mdadm superblock question.

From: H. Peter Anvin
Date: Sun Feb 14 2010 - 16:18:46 EST


On 02/14/2010 12:25 PM, Asdo wrote:
> I don't understand...
> In a system we have, the root filesystem on a raid-6 which is on second
> (and last) partitions of many disks.
> It always assembled correctly, it never tried to assemble the whole device.
> (on the first partition there is a raid1 with boot)
> So what's the problem exactly with not marking the beginning?

In Fedora 12, for example, Dracut tries to make the distinction between
whole RAID device and a partition device, and utterly fails -- often
resulting in data loss.

With a pointer to the beginning this would have been a trivial thing to
detect.

IMO it would make sense to support autoassemble for 1.0 superblocks, and
making them the default. The purpose would be to get everyone off 0.9.
However, *any* default is better than 1.1.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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