Re: Data corruption on software RAID

[Mario 'BitKoenig' Holbe <Mario.Holbe@TU-Ilmenau.DE>]

Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> wrote:
> During source code review, I found an unprobable but possible data 
> corruption on RAID-1 and on DM-RAID-1. (I'm not sure about RAID-4,5,6).
>
> The RAID code was enhanced with bitmaps in 2.6.13.
...
> The developers assume that when all writes to the region finish, the 
> region is in-sync.

Just for the records: You don't need bitmaps for that, this happens on
plain non-bitmapped devices as well.
I had an interesting discussion about this with Heinz Mauelshagen on the
linux-raid list back in early 2006 starting with
	Message-ID: <du6t39$be5$1@sea.gmane.org>

And it's not that unlikely at all. I experience such inconsistencies
regularly on ext2/3 filesystems with heavy inode fluctuations (for
example via cp -al; rsync, like rsnapshot does). I periodically sync
these inconsistencies manual. However, it always seems to appear with
inode removal only, which is rather harmless.


regards
   Mario
-- 
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only be, as is generally accepted, "Don't try to fly too high," or
whether it might also be thought of as, "Forget the wax and feathers
and do a better job on the wings."            -- Stanley Kubrick