From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Helmut Hullen" Subject: Re: btrfs device scan Date: 12 May 2011 08:25:00 +0200 Message-ID: References: <4DCB7195.30208@gmail.com> Reply-To: helmut@hullen.de Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII To: linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <4DCB7195.30208@gmail.com> List-ID: Hallo, Victor, Du meintest am 12.05.11: >>> I have a couple computers running 2.6.38 >>> (Ubuntu Natty 2.6.38-8-generic), and on both of them >>> "btrfs device scan" comes back with nothing other than >>> "failed to read /dev/sr0" [..] > $ btrfs device scan > Scanning for Btrfs filesystems > failed to read /dev/sr0 That's a "well known" error; "scan" tries block devices which really cannot contain a btrfs filesystem. People who don't use "udev" get a lot of more "failed to read" messages; "scan" seems to try every block device which exists in "/dev". Maybe it's more reliable if "scan" doesn't look into "dev" but uses "/ proc/partitions". > $ btrfs filesystem show > failed to read /dev/sr0 > Label: 'server-backup' uuid: b927ead9-2e5b-4ee8-b9f4-7209177c49d8 > Total devices 2 FS bytes used 603.17GB > devid 1 size 1.36TB used 605.28GB path /dev/sdb1 > devid 2 size 1.36TB used 605.26GB path /dev/sdc1 That shows that (in this case) you can ignore the "scan" message. Viele Gruesse! Helmut