From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout.teamix.de ([194.150.191.118]:40935 "EHLO mailout.teamix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751741AbcKPKzg (ORCPT ); Wed, 16 Nov 2016 05:55:36 -0500 From: Martin Steigerwald To: Roman Mamedov CC: , Martin Subject: Re: degraded BTRFS RAID 1 not mountable: open_ctree failed, unable to find block group for 0 Date: Wed, 16 Nov 2016 11:55:32 +0100 Message-ID: <3374757.aMVjisyVFB@merkaba> In-Reply-To: <20161116154336.543a326b@natsu> References: <18970348.FUMEOFOSb3@merkaba> <20161116154336.543a326b@natsu> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Sender: linux-btrfs-owner@vger.kernel.org List-ID: Am Mittwoch, 16. November 2016, 15:43:36 CET schrieb Roman Mamedov: > On Wed, 16 Nov 2016 11:25:00 +0100 > > Martin Steigerwald wrote: > > merkaba:~> mount -o degraded,clear_cache /dev/satafp1/backup /mnt/zeit > > mount: Falscher Dateisystemtyp, ungültige Optionen, der > > Superblock von /dev/mapper/satafp1-backup ist beschädigt, fehlende > > Kodierungsseite oder ein anderer Fehler > > > > Manchmal liefert das Systemprotokoll wertvolle Informationen – > > versuchen Sie dmesg | tail oder ähnlich > > > > merkaba:~#32> dmesg | tail -6 > > [ 3080.120687] BTRFS info (device dm-13): allowing degraded mounts > > [ 3080.120699] BTRFS info (device dm-13): force clearing of disk cache > > [ 3080.120703] BTRFS info (device dm-13): disk space caching is > > enabled > > [ 3080.120706] BTRFS info (device dm-13): has skinny extents > > [ 3080.150957] BTRFS warning (device dm-13): missing devices (1) > > exceeds the limit (0), writeable mount is not allowed > > [ 3080.195941] BTRFS: open_ctree failed > > I have to wonder did you read the above message? What you need at this point > is simply "-o degraded,ro". But I don't see that tried anywhere down the > line. > > See also (or try): https://patchwork.kernel.org/patch/9419189/ Actually I read that one, but I read more into it than what it was saying: I read into it that BTRFS would automatically use a read only mount. merkaba:~> mount -o degraded,ro /dev/satafp1/daten /mnt/zeit actually really works. *Thank you*, Roman. I do think that above kernel messages invite such a kind of interpretation tough. I took the "BTRFS: open_ctree failed" message as indicative to some structural issue with the filesystem. So mounting work although for some reason scrubbing is aborted (I had this issue a long time ago on my laptop as well). After removing /var/lib/btrfs scrub status file for the filesystem: merkaba:~> btrfs scrub start /mnt/zeit scrub started on /mnt/zeit, fsid […] (pid=9054) merkaba:~> btrfs scrub status /mnt/zeit scrub status for […] scrub started at Wed Nov 16 11:52:56 2016 and was aborted after 00:00:00 total bytes scrubbed: 0.00B with 0 errors Anyway, I will now just rsync off the files. Interestingly enough btrfs restore complained about looping over certain files… lets see whether the rsync or btrfs send/receive proceeds through. Ciao, -- Martin Steigerwald | Trainer teamix GmbH Südwestpark 43 90449 Nürnberg Tel.: +49 911 30999 55 | Fax: +49 911 30999 99 mail: martin.steigerwald@teamix.de | web: http://www.teamix.de | blog: http://blog.teamix.de Amtsgericht Nürnberg, HRB 18320 | Geschäftsführer: Oliver Kügow, Richard Müller teamix Support Hotline: +49 911 30999-112 *** Bitte liken Sie uns auf Facebook: facebook.com/teamix ***