Bug#534470: Using mdadm 2.6.7.2 to assemble a raid array created with mdadm 1.9.0 will corrupt it making mdadm 1.9.0 to crash when trying to reassemble

[Neil Brown]

On Wed, 27 Jan 2010 14:13:36 +1300
martin f krafft <madduck at debian.org> wrote:

> also sprach RUSSOTTO François-Xavier 200103 <francois-xavier.russotto at cea.fr> [2009.12.02.0407 +1300]:
> > As I suggested to Neil: prior to auto-remount a raid array, the
> > raid tool should perform a version checking so that, at least,
> > user is warned that the raid array might be corrupt performing
> > such operation.  
> 
> Neil, does this sound like a feasible solution to
> http://bugs.debian.org/534470?

I don't think so.
We really want old arrays to work smoothly on new kernels.
To avoid a repartition of the original problem we would need not just a
message, but an option not to assemble the array and that would be awkward for
people normally upgrading their system.

So I don't think there is a solution for this problem that does not introduce
other problems.
It does not affect x86 architectures, and is only a problem if you move to a
new kernel, then back to an old kernel.  So hopefully it will be very rare.

Sorry.

NeilBrown