Re: [testcase] test your fs/storage stack (was Re: [patch] ext2/3:document conditions when reliable operation is possible)

From: Pavel Machek
Date: Thu Sep 03 2009 - 04:55:42 EST


Hi!

>> However, thinking about how to _fix_ a problem is predicated on acknowledging
>> that there actually _is_ a problem. "The hardware is not physically damaged
>> but your data was lost" sounds to me like a software problem, and thus
>> something software could at least _attempt_ to address. "There's millions of
>> 'em, Linux can't cope" doesn't seem like a useful approach.
>
> no other OS avoids this problem either.
>
> I actually don't see how you can do this from userspace, because when you
> write to the device you have _no_ idea where on the device your data will
> actually land.

It certainly is not easy. Self-correcting codes could probably be
used, but that would be very special, very slow, and very
non-standard. (Basically... we could design filesystem so that it
would survive damage of arbitrarily 512K on disk -- using
self-correcting codes in CD-like manner). I'm not sure if it would be
practical.

Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/