[Beowulf] MD check/scrub

Leif Nixon nixon at nsc.liu.se
Wed Nov 14 03:15:01 PST 2007

Mark Hahn <hahn at mcmaster.ca> writes:

>> If they find an inconsistent stripe they don't try to identify the
>> corrupt block. Instead, they dumbly *recompute P and Q*, which of
>> course makes the stripe consistent, but *leaves the corrupt data in
>> place*.
> I'm skeptical that MD would be so willfully stupid.

Me too, but I'm looking at a trashed test file at this very moment.

> did you conclude this from reading the code, empirical testing, or
> from the author?

Empirical testing, using raid 6 over file backed loop devices. I
*hope* there is something wrong with our methodology. We'll need to do
a proper summary of our findings and raise the issue on the linux-raid
mailing list.

Leif Nixon                       -            Systems expert
National Supercomputer Centre    -      Linkoping University

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