From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from len.romanrm.net ([195.154.117.182]:34016 "EHLO len.romanrm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752195AbcKPKnj (ORCPT ); Wed, 16 Nov 2016 05:43:39 -0500 Date: Wed, 16 Nov 2016 15:43:36 +0500 From: Roman Mamedov To: Martin Steigerwald Cc: , Martin Subject: Re: degraded BTRFS RAID 1 not mountable: open_ctree failed, unable to find block group for 0 Message-ID: <20161116154336.543a326b@natsu> In-Reply-To: <18970348.FUMEOFOSb3@merkaba> References: <18970348.FUMEOFOSb3@merkaba> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: 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/ -- With respect, Roman