On 01/20/2011 10:18 PM, Carl Cook wrote: > > Well I've just tried to add a disk to another, but it fails. I > created the first (starting with no traditional partitions) with: # > mkfs.btrfs /dev/sdb > > Then I mounted it to /media/backups and put lots of files on it. I > shut down the system, added another disk. Set it up with: # > mkfs.btrfs /dev/sdc WARNING! - Btrfs Btrfs v0.19 IS EXPERIMENTAL > WARNING! - see http://btrfs.wiki.kernel.org before using fs created > label (null) on /dev/sdc nodesize 4096 leafsize 4096 sectorsize 4096 > size 1.82TB Btrfs Btrfs v0.19 # btrfs device scan Scanning for Btrfs > filesystems # (... Nothing? Not even my known mounted sdb drive?) # > btrfs device add /dev/sdc /media/backups ERROR: error adding the > device '/dev/sdc' > > It gives no clue as to what might possibly be the problem. I want > raid0. 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 If you shutdown the system, at the reboot you should "scan" all the device in order to find the btrfs ones # find the btrfs device btrfs device scan # mount the filesystem mount /dev/sdb /media/backups # you can use also /dev/sdc > > Also I can not understand this: "Note: While subvolumes can be > created anywhere in the filesystem tree, in order to be mounted by > name a subvolume or snapshot must be in the root of the btrfs > filesystem." > > I want to do this, but do not know what this means. Suppose to have a btrfs filesystem in /dev/sdb mount /dev/sdb /media/backup mkidr /media/backup/dir-1 <create a lot of file under /media/backup> # make a snapshot btrfs filesystem snapshot /media/backup /media/backup/snapshot-2 # make another snapshot btrfs filesystem snapshot /media/backup /media/backup/dir-1/snapshot-3 # umount the filesystem umount /media/backup # mount snapshot-2 directly mount -o subvol=snapshot-2 /dev/sdb /media/backup # if you try to mount snapshot-3 directly, you fail because this # snapshot is not under the root of the btrfs filesystem mount -o subvol=dir-1/snapshot-3 /dev/sdb /media/backup # -> error If you look at the output of the command "btrfs subvolume list <path>" you can find the id of every subvolume. It is possible to use this ID to mount directly a subvolume. This permits to mount a "non-root" subvolume. > Tentatively I've > created a BTRFS volume and mounted it on /media/backups. I then > created subvolumes as backup-hex, backup-droog, snaps-hex and > snaps-droog. When I created a snapshot it created a subdir under > snaps-hex called hex-root. > > It won't allow me to remove snapshots. (Debian Testing) Which kenel version debian testing uses ? > Also does anyone know how to create a shapshot with the current date > in the name? btrfs filesystem snapshot / /snapshot-$(date +"%Y-%m-%d") > -- To unsubscribe from this list: send the line "unsubscribe > linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html . > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
