Hello once more...
I'm on Ubuntu 13.04 with Ubuntu kernel 3.8.0-19-lowlatency and
Btrfs v0.20-rc1.
(Did I say that before...? *G*)
Okay, ATM I'm writing a script for creating snapshots for "backups" of
all my btrfs filesystems. I come from a FreeBSD / Solaris background
with heavy use of ZFS.
In ZFS, it's very easy to create snapshots of all "zpools"
("filesystems") of the system, like so:
SnapName=backup.`date +%Y%m%d--%H%M%S`
zpool list -Ho name | while read zpool; do
zfs snapshot -r $zpool@$SnapName &
done ; wait
Well… How to do something like this with btrfs? I do _not_ want to
have to manually list the filesystems/subvolumes I've got in some
script or configuration file.
Where I'm hanging right now, is that I can't seem to figure out a
"bullet proof" way to find all the subvolumes of the filesystems I
might have.
I've got this:
root@ask-home:~# btrfs fi show
failed to read /dev/sr0
Label: 'Data' uuid: 7d2eb10f-aced-4d41-bb7f-7badbf075b6a
Total devices 1 FS bytes used 27.96GB
devid 1 size 35.00GB used 35.00GB path /dev/dm-0
Label: 'KernBtrfs' uuid: 8b16bc2a-43e3-40da-89f5-7b333c6682f3
Total devices 1 FS bytes used 655.05MB
devid 1 size 11.85GB used 6.04GB path /dev/sda11
Btrfs v0.20-rc1
root@ask-home:~# mount -t btrfs
/dev/mapper/ssd-Data on /data type btrfs (rw,noatime,ssd,discard)
/dev/mapper/ssd-Data on /home type btrfs (rw,noatime,ssd,discard,subvol=home)
/dev/sda11 on /data/Kernel/KernBtrfs type btrfs (rw,noatime)
Now, how would I find all the subvolumes of the btrfs with the label
"Data" (or uuid 7d...) or /dev/dm-0? "btrfs subvolume list" only seems
to operate on where a btrfs is mounted. It works on "path".
I could do "btrfs subv list -a /data", but how would I figure out,
that "/data" is the "root" of the filesystem with uuid 7d...?
For now, I do something like this (-> http://pastebin.com/u08ub1i8):
SnapName=backup.`date +%Y%m%d--%H%M%S`
btrfs fi show 2>/dev/null | awk '/ path / {print $NF}' | while read path; do
SafePath=`echo "$path" | tr / .`
TmpMountDir=`mktemp -d /tmp/.btrfs.mount.$SafePath.XXXXXX`
mount -t btrfs $path $TmpMountDir
(btrfs subv list -ar $TmpMountDir; btrfs subv list -a $TmpMountDir)
| sort | uniq -u | while read _id Id _gen Gen _top _level Toplevel
_path Path; do
btrfs subv snaps -r "$TmpMountDir/$Path" "$TmpMountDir/$Path.$SnapName"
done
umount $TmpMountDir
rmdir $TmpMountDir
done
Now, this works, but seems "somewhat" complicated... But
maybe I'm just spoiled by ZFS ;)
Is there an easier way to achieve what I want? I want to achieve:
Creating recursive snapshots for all filesystems
;)
Thanks,
Alexander
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