* [Validation] How to properly use the subvolume and snapshot for a backup method
@ 2011-05-25 3:49 Sylvain Alain
2011-05-25 17:34 ` Goffredo Baroncelli
0 siblings, 1 reply; 2+ messages in thread
From: Sylvain Alain @ 2011-05-25 3:49 UTC (permalink / raw)
To: linux-btrfs
Hi everyone, first of all, I want to say that I'm learning how to use
BTRFS and I really enjoy all the subvolume and the snapshot features.
Also, I'm a backup freak :P
Basically, I have 4 questions :
1. I would like to know what is the best way to install a Linux
distribution inside a BTRFS partition ? I mean, do I install it directly
inside the subvolid=0 or I create a subvolume for exemple @root to leave
the subvolid=0 clean and without any data, of course only subvolume and
then I install my distro inside the @root subvolume ? I'm asking that,
because I saw that Ubuntu 11.04 use the subvolume @ and @home to install
the distribution files so, the subvolid=0 is clean.
I saw that because at boot time, the /boot/grub/grub.cfg use this param
with Grub2 : rootflags=subvol=@
2. I would like to know if this Live backup method is correct ?
+++++
My /dev/sda2 contains a @root subvolume that contains my distribution,
my /home directory is inside an another subvolume that is at the same
level that @root.
# mkdir /mnt/disklayout
# mount /dev/sda2 /mnt/disklayout -o subvolid=0
# cd /mnt/disklayout
# btrfs subvolume snapshot @root snapshot-@racine-live
# btrfs subvolume snapshot @home snapshot-@home-live
# mount /dev/sdb1 /mnt/backup -o subvol=@backup
# time rsync -aHA --del --force --stats --progress
snapshot-@racine-live/ /mnt/backup/funtoo
# time rsync -aHA --del --force --stats --progress snapshot-@home-live/
/mnt/backup/funtoo/home
# time rsync -aHA --del --force --stats --progress /boot/
/mnt/backup/funtoo/boot
# cd /mnt/disklayout
# btrfs subvolume delete snapshot-@root-live
# btrfs subvolume delete snapshot-@home-live
# cd /
# umount /mnt/disklayout
Creation of the snapshot :
# cd /
# umount /mnt/backup
# mount /dev/sdb1 /mnt/backup -o subvolid=0
# cd /mnt/backup
# btrfs subvolume snapshot @backup @snap-20110502
# btrfs subvolume list .
# cd /mnt/backup
# ls -la
# cd @snap-20110502
# ls -la
# cd /
# umount /mnt/backup
------
3. Is there any objection to use a snapshot name or a subvolume that
start with a @ ?
4. Finally,I would like to know if we can rename subvolume ?
The best example is this : I crash my box but I made earlier a snapshot
that is named @snap-20110502 inside my subvolid=0. Now that my @root is
brain dead, I would like to delete it and rename the @snap-20110502 to
@root ?
Is this possible and if so, can I use the mv command or something else ?
I'm sure that I will need to boot with a LiveCD to do so, but for the
rest, is this possible ?
Thanks you very much !!!
--
Salut
alp
Sylvain
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Validation] How to properly use the subvolume and snapshot for a backup method
2011-05-25 3:49 [Validation] How to properly use the subvolume and snapshot for a backup method Sylvain Alain
@ 2011-05-25 17:34 ` Goffredo Baroncelli
0 siblings, 0 replies; 2+ messages in thread
From: Goffredo Baroncelli @ 2011-05-25 17:34 UTC (permalink / raw)
To: Sylvain Alain; +Cc: linux-btrfs
On 05/25/2011 05:49 AM, Sylvain Alain wrote:
> Hi everyone, first of all, I want to say that I'm learning how to use
> BTRFS and I really enjoy all the subvolume and the snapshot features.
>
> Also, I'm a backup freak :P
>
> Basically, I have 4 questions :
>
> 1. I would like to know what is the best way to install a Linux
> distribution inside a BTRFS partition ? I mean, do I install it directly
> inside the subvolid=0 or I create a subvolume for exemple @root to leave
> the subvolid=0 clean and without any data, of course only subvolume and
> then I install my distro inside the @root subvolume ? I'm asking that,
> because I saw that Ubuntu 11.04 use the subvolume @ and @home to install
> the distribution files so, the subvolid=0 is clean.
> I saw that because at boot time, the /boot/grub/grub.cfg use this param
> with Grub2 : rootflags=subvol=@
I do so
>
> 2. I would like to know if this Live backup method is correct ?
>
> +++++
> My /dev/sda2 contains a @root subvolume that contains my distribution,
> my /home directory is inside an another subvolume that is at the same
> level that @root.
>
> # mkdir /mnt/disklayout
> # mount /dev/sda2 /mnt/disklayout -o subvolid=0
>
> # cd /mnt/disklayout
> # btrfs subvolume snapshot @root snapshot-@racine-live
> # btrfs subvolume snapshot @home snapshot-@home-live
>
> # mount /dev/sdb1 /mnt/backup -o subvol=@backup
>
> # time rsync -aHA --del --force --stats --progress
> snapshot-@racine-live/ /mnt/backup/funtoo
> # time rsync -aHA --del --force --stats --progress snapshot-@home-live/
> /mnt/backup/funtoo/home
> # time rsync -aHA --del --force --stats --progress /boot/
> /mnt/backup/funtoo/boot
>
> # cd /mnt/disklayout
> # btrfs subvolume delete snapshot-@root-live
> # btrfs subvolume delete snapshot-@home-live
>
> # cd /
> # umount /mnt/disklayout
>
> Creation of the snapshot :
>
> # cd /
> # umount /mnt/backup
> # mount /dev/sdb1 /mnt/backup -o subvolid=0
>
> # cd /mnt/backup
> # btrfs subvolume snapshot @backup @snap-20110502
> # btrfs subvolume list .
>
> # cd /mnt/backup
> # ls -la
> # cd @snap-20110502
> # ls -la
> # cd /
> # umount /mnt/backup
to me it seems correctly
>
> ------
>
> 3. Is there any objection to use a snapshot name or a subvolume that
> start with a @ ?
>
> 4. Finally,I would like to know if we can rename subvolume ?
I did without trouble
>
> The best example is this : I crash my box but I made earlier a snapshot
> that is named @snap-20110502 inside my subvolid=0. Now that my @root is
> brain dead, I would like to delete it and rename the @snap-20110502 to
> @root ?
>
> Is this possible and if so, can I use the mv command or something else ?
> I'm sure that I will need to boot with a LiveCD to do so, but for the
> rest, is this possible ?
I tweaked a bit the grub script (under /etc/grub.d/);now when I run
"update-grub", the grub.cfg contains also some entries which permit do
boot in the snapshot subvolume. Basycally these entries contains the
replace the parameter "rootflags=subvol=@" in
"rootflags=subvol=<subvolume name>". Is far to be optimal, but doing so
I don't need any LiveCD.
For example in a snapshot I am testing systemd ...
>
>
> Thanks you very much !!!
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2011-05-25 3:49 [Validation] How to properly use the subvolume and snapshot for a backup method Sylvain Alain
2011-05-25 17:34 ` Goffredo Baroncelli
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