Re: raid6 check/repair

pg_lxra@lxra.for.sabi.co.UK (Peter Grandi) writes:

ms> I just want to give another suggestion. It may or may not be
ms> possible to repair inconsistent arrays but in either way some
ms> code there MUST at least warn the administrator that
ms> something (may) went wrong.

tn> Agreed.

That sounds instead quite extraordinary to me because it is not
clear how to define ''inconsistency'' in the general case never
mind detect it reliably, and never mind knowing when it is found
how to determine which are the good data bits and which are the
bad.

I don't quite follow you. Having a basic consistency check utility for
a raid array is to me as obvious as having an fsck utility for a file
system.

Now I am starting to think that this discussion is based on the
curious assumption that storage subsystems should solve the so
called ''byzantine generals'' problem, that is to operate reliably
in the presence of unreliable communications and storage.

I don't think anyone is proposing to solve that problem. However, an
occasional slight nod in acknowledgment of the fact that real world
communications and storage *are* unreliable wouldn't be out of place.

-- 
Leif Nixon                       -            Systems expert
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National Supercomputer Centre    -      Linkoping University
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