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From: Chris Murphy <lists@colorremedies.com>
To: "Jason D. Michaelson" <jasondmichaelson@gmail.com>
Cc: Chris Murphy <lists@colorremedies.com>,
	Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: raid6 file system in a bad state
Date: Tue, 11 Oct 2016 10:06:53 -0600	[thread overview]
Message-ID: <CAJCQCtQ12AZQ9x2ddSSceGHpWYvB7sSVE0qty+=Ln9oibmiHRw@mail.gmail.com> (raw)
In-Reply-To: <5e8501d223d7$715a9bb0$540fd310$@com>

On Tue, Oct 11, 2016 at 9:52 AM, Jason D. Michaelson
<jasondmichaelson@gmail.com> wrote:

>> btrfs rescue super-recover -v <dev>
>
> root@castor:~/logs# btrfs rescue super-recover -v /dev/sda
> All Devices:
>         Device: id = 2, name = /dev/sdh
>         Device: id = 3, name = /dev/sdd
>         Device: id = 5, name = /dev/sdf
>         Device: id = 6, name = /dev/sde
>         Device: id = 4, name = /dev/sdg
>         Device: id = 1, name = /dev/sda
>
> Before Recovering:
>         [All good supers]:
>                 device name = /dev/sdd
>                 superblock bytenr = 65536
>
>                 device name = /dev/sdd
>                 superblock bytenr = 67108864
>
>                 device name = /dev/sdd
>                 superblock bytenr = 274877906944
>
>                 device name = /dev/sdf
>                 superblock bytenr = 65536
>
>                 device name = /dev/sdf
>                 superblock bytenr = 67108864
>
>                 device name = /dev/sdf
>                 superblock bytenr = 274877906944
>
>                 device name = /dev/sde
>                 superblock bytenr = 65536
>
>                 device name = /dev/sde
>                 superblock bytenr = 67108864
>
>                 device name = /dev/sde
>                 superblock bytenr = 274877906944
>
>                 device name = /dev/sdg
>                 superblock bytenr = 65536
>
>                 device name = /dev/sdg
>                 superblock bytenr = 67108864
>
>                 device name = /dev/sdg
>                 superblock bytenr = 274877906944
>
>                 device name = /dev/sda
>                 superblock bytenr = 65536
>
>                 device name = /dev/sda
>                 superblock bytenr = 67108864
>
>                 device name = /dev/sda
>                 superblock bytenr = 274877906944
>
>         [All bad supers]:
>                 device name = /dev/sdh
>                 superblock bytenr = 65536
>
>                 device name = /dev/sdh
>                 superblock bytenr = 67108864
>
>                 device name = /dev/sdh
>                 superblock bytenr = 274877906944
>
>
> Make sure this is a btrfs disk otherwise the tool will destroy other fs, Are you sure? [y/N]: n
> Aborted to recover bad superblocks
>
> I aborted this waiting for instructions on whether to proceed from the list.


Bad superblocks can't be a good thing and would only cause confusion.
I'd think that a known bad superblock would be ignored at mount time
and even by btrfs-find-root, or maybe even replaced like any other
kind of known bad metadata where good copies are available.

btrfs-show-super -f /dev/sda
btrfs-show-super -f /dev/sdh


Find out what the difference is between good and bad supers.


-- 
Chris Murphy

  reply	other threads:[~2016-10-11 16:07 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-10 16:04 raid6 file system in a bad state Jason D. Michaelson
2016-10-10 20:59 ` Chris Murphy
     [not found]   ` <5ce201d22364$96702780$c3507680$@com>
2016-10-11  4:23     ` Chris Murphy
2016-10-11 15:52       ` Jason D. Michaelson
2016-10-11 16:06         ` Chris Murphy [this message]
2016-10-11 16:10           ` Jason D. Michaelson
2016-10-11 17:41             ` Chris Murphy
     [not found]               ` <5e8701d223f1$c7ea0960$57be1c20$@com>
2016-10-11 20:38                 ` Chris Murphy
2016-10-12 17:59                   ` Jason D. Michaelson
2016-10-12 19:36                     ` Chris Murphy
2016-10-14 21:54                       ` Chris Murphy
2016-10-17 18:52                         ` Jason D. Michaelson

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