From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Helmut Hullen" Subject: Re: Adding a disk fails Date: 21 Jan 2011 11:51:00 +0100 Message-ID: References: <4D38B382.1050709@libero.it> 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: <4D38B382.1050709@libero.it> List-ID: Hallo, Goffredo, Du meintest am 20.01.11: > To add another disk you don't have to run mkfs.btrfs. For example: > # add the first disk > mkfs.btrfs /dev/sdb > # mount the disk > mount /dev/sdb /media/backups > # add another disk to the first one > btrfs device add /dev/sdc /media/backup > Note1: the filesystem has to be mounted > Note2: the medatada will be in raid1, the data in raid0 Note 3: if the disk has been used (especially under btrfs) you should first delete old partitioning data etc: dd if=/dev/zero of=/dev/sdb count=1000 dd if=/dev/zero of=/dev/sdc count=1000 I've just tried your recipe with two devices I had used for other btrfs experiments: btrfs filesystem show 2>/dev/null shows my new wishes, and it shows the old settings too. But writing 1000 blocks seems to be not enough - sometimes I'll try bigger numbers. What happens with the old (and now unwanted) settings? By the way: I nee "2>/dev/null" because the actual git version always tries to show all block devices which it finds in "/dev" (no: I don't use "udev"). Viele Gruesse! Helmut