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Subject: Re: Btrfs scrub failure for raid 6 kernel 4.3
To: Chris Murphy <lists@colorremedies.com>
Cc: Btrfs BTRFS <linux-btrfs@vger.kernel.org>
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From: Waxhead <waxhead@online.no>
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Date: Wed, 30 Dec 2015 19:31:59 +0100
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Chris Murphy wrote:
> Well all the generations on all devices are now the same, and so are
> the chunk trees. I haven't looked at them in detail to see if there
> are any discrepancies among them.
>
> If you don't care much for this file system, then you could try btrfs
> check --repair, using btrfs-progs 4.3.1 or integration branch. I have
> no idea where btrfsck repair is at with raid56.
>
> On the one hand, corruption should be fixed by scrub. But scrub fails
> with a kernel trace. Maybe btrfs check --repair can fix the tree block
> corruption since scrub can't, and then if that corruption is fixed,
> possibly scrub will work.
>
I could not care less about this particular filesystem as I wrote in the 
original post. It's just for having some fun with btrfs. What I find 
troublesome is that corrupting one (or even two) drives in a Raid6 
config fails. Granted the filesystem "works" e.g. I can mount it and 
access files, but I get a input/output error on a file on this 
filesystem and btrfs only shows warning (not errors) on device sdg1 
where the csum failed.
A raid6 setup should work fine even if two missing disks (or in this 
case chunks of data) is missing and even if I don't care about this 
filesystem I care about btrfs getting stable ;) so if I can help I'll 
keep this filesystem around for a little longer!