From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f48.google.com ([74.125.82.48]:35588 "EHLO mail-wm0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750859AbcGGMYu (ORCPT ); Thu, 7 Jul 2016 08:24:50 -0400 Received: by mail-wm0-f48.google.com with SMTP id z126so146470169wme.0 for ; Thu, 07 Jul 2016 05:24:50 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: From: Gonzalo Gomez-Arrue Azpiazu Date: Thu, 7 Jul 2016 15:24:29 +0300 Message-ID: Subject: Re: Unable to mount degraded RAID5 To: linux-btrfs@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Thanks a lot, your will to help out someone you do not know (and who is obviously way over his depth) is inspiring. This is what it says: btrfs rescue super-recover -v /dev/sdc1 All Devices: Device: id = 3, name = /dev/sdd1 Device: id = 1, name = /dev/sdc1 Before Recovering: [All good supers]: device name = /dev/sdd1 superblock bytenr = 65536 device name = /dev/sdd1 superblock bytenr = 67108864 device name = /dev/sdd1 superblock bytenr = 274877906944 device name = /dev/sdc1 superblock bytenr = 65536 device name = /dev/sdc1 superblock bytenr = 67108864 device name = /dev/sdc1 superblock bytenr = 274877906944 [All bad supers]: All supers are valid, no need to recover Any suggestion on what to do next? (again, really appreciated - I hope to be able to give back the support I am receiving at some point!) On Wed, Jul 6, 2016 at 9:19 PM, Chris Murphy wrote: > On Wed, Jul 6, 2016 at 11:12 AM, Gonzalo Gomez-Arrue Azpiazu > wrote: >> Hello, >> >> I had a RAID5 with 3 disks and one failed; now the filesystem cannot be mounted. >> >> None of the recommendations that I found seem to work. The situation >> seems to be similar to this one: >> http://www.spinics.net/lists/linux-btrfs/msg56825.html >> >> Any suggestion on what to try next? > > Basically if you are degraded *and* it runs into additional errors, > then it's broken because raid5 only protects against one device error. > The main problem is if it can't read the chunk root it's hard for any > tool to recover data because the chunk tree mapping is vital to > finding data. > > What do you get for: > btrfs rescue super-recover -v /dev/sdc1 > > It's a problem with the chunk tree because all of your super blocks > point to the same chunk tree root so there isn't another one to try. > >>sudo btrfs-find-root /dev/sdc1 >>warning, device 2 is missing >>Couldn't read chunk root >>Open ctree failed > > It's bad news. I'm not even sure 'btrfs restore' can help this case. > > > -- > Chris Murphy