[PLUG] question on converting ext3/ext4 file systems to btrfs

[tomas.kuchta.lists at gmail.com]

Maybe 6 years ago I converted couple of hundred partitions to btrfs on SLES/SLED
- Motivation: OS/update snapshots significantly simplified staged testing and
deployment with supper simple and fast roll back. I had no problems with ext3/4-
->btrfs conversion back then.

That said, I have not needed/used it for years. As far as I can tell, there is
no negative chatter about it on openSuSE support mailing list "ever".

If you are thinking about converting OS partitions - I would not recommend doing
that. It will work, I am sure, but it would likely complicate your life because
btrfs is different kind of animal when it comes to OS install.

OpenSuSE/SLES/SLED takes advantage of sub-volume handling/configuration, so it
wants to create following OS vol/sub-vol structure:

UUID=09...495  /                       btrfs  defaults                      0  0
UUID=09...495  /.snapshots             btrfs  subvol=/@/.snapshots          0  0
UUID=99...a87  swap                    swap   defaults                      0  0
UUID=09...495  /var                    btrfs  subvol=/@/var                 0  0
UUID=09...495  /usr/local              btrfs  subvol=/@/usr/local           0  0
UUID=09...495  /tmp                    btrfs  subvol=/@/tmp                 0  0
UUID=09...495  /srv                    btrfs  subvol=/@/srv                 0  0
UUID=09...495  /root                   btrfs  subvol=/@/root                0  0
UUID=09...495  /opt                    btrfs  subvol=/@/opt                 0  0
UUID=09...495  /boot/grub2/x86_64-efi  btrfs  subvol=/@/boot/grub2/x86_64-
efi  0  0
UUID=09...495  /boot/grub2/i386-pc     btrfs  subvol=/@/boot/grub2/i386-pc  0  0
UUID=78FE-6619 /boot/efi               vfat   defaults                      0  0

So, if you are converting traditional 1-2 partition ext4 OS structure random
things might cause you various headaches over time.

Best luck,
Tomas

On Mon, 2020-08-10 at 16:42 -0700, logical american wrote:
> I am thinking of converting my ext3/4 file partitions to btrfs type, 
> since Suse is pushing for this as their default file system. Has anyone 
> had any trouble with the conversion or with btrfs itself? I have about 
> 8-10 partitions to change over.
> 
> - Randall
> 
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