From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout05.t-online.de ([194.25.134.82]:32868 "EHLO mailout05.t-online.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753441Ab2HEKuK (ORCPT ); Sun, 5 Aug 2012 06:50:10 -0400 Date: 05 Aug 2012 12:46:00 +0200 From: Hullen@t-online.de (Helmut Hullen) To: linux-btrfs@vger.kernel.org Message-ID: In-Reply-To: Subject: Re: filesystem show still has stale filesystem MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Reply-To: helmut@hullen.de Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hallo, Florian, Du meintest am 05.08.12: > I was playing with btrfs and accidentally formatted the disk directly > (/dev/sdb instead of sdb1). Since then I rewrote the GPT partition > table, recreated the partition and ran btrfs device scan. Still, > btrfs filesystem show prints: > root@horus /mnt # btrfs fi sh --all-devices > failed to read /dev/sr0: No medium found > Label: 'test' uuid: ffab72f2-eff1-4ac8-a694-d56dd84fda24 > Total devices 1 FS bytes used 28.00KB > devid 1 size 2.73TB used 2.04GB path /dev/sdb > Label: 'home' uuid: c465d715-098a-4d0d-bebc-6aa51f4cb349 > Total devices 1 FS bytes used 28.00KB > devid 1 size 2.73TB used 2.04GB path /dev/sdb1 "formatting" leaves most bytes on the disk untouched. If you really want to use only /dev/sdb (or only /dev/sdb1) then you should first fill many bytes at the beginning of the disk with zeros. Some months ago someone had told the minimum; I have forgotten this value. But something like dd if=/dev/zero of=/dev/sdb bs=1M count=10 should do the job. And then "mkfs.btrfs" creates the (only) wanted partition(s). Viele Gruesse! Helmut