I have openSUSE 13.1 (64-bit) with a KDE desktop environment. Both Root and Home use the EXT4 filesystem. I would like to upgrade to v. 13.2 while at the same time preserving “/home” so that I don’t have to start over with customizations etc. It is my understanding that v. 13.2 offers to create a root partition with Btrfs. So, can I have “/” as Btrfs and “/home” as EXT4? PS: I understand that during the upgrade to v. 13.2 I can use EXT4 for root too, but I am just curious to know whether I can mix filesystems within the same installation and what the repercussions are!
The simple answer is yes you can mix file systems on separate partitions, so to be clear:
Is your /home on a separate partition to root?
What method are you planning to use for the upgrade?
Yes, “/” and “/home” are separate partitions.
What method are you planning to use for the upgrade?
I am planning on booting up my PC with the DVD and selecting the Update mode, if that option is still offered in v. 13.2. I would then tell openSUSE to format the “/” partition, install using the Btrfs filesystem and to leave “/home” alone.
I believe it is offered for 13.2, but I don’t use that one (“zypper dup” for an online upgrade here).
For “/” on Btrfs, you will get frequent snapshots and Snapper installed by default for snapshot management. Have you read the openSUSE official documentation and/or forum postings about using Btrfs and Snapper? They deal with requirements for increasing space on “/”, and reducing the frequency and retention of snapshots to reduce the storage overhead, among other things.
Confirming btrfs root/ and ext4 /home on a separate partition on the laptop used to write this, installed from the DVD, but please NOTE:
- if you are going to “format to btrfs” you are losing all your installed software; this is not an “upgrade”, it is a “clean installation” wiping all that is currently on root/.
- nonetheless it is possible to keep all user data on /home (but be sure NOT to format to ext4, just leave /home alone);
- anyway it is advisable to backup /home as well, just in case something goes wrong…
Maybe it is possible to transform an ext4 to a btrfs with some tool, but I don’t think this is what the DVD installer is offering to do.
Thanks consuses and OrsoBruno for your tips.
What I am planning on doing is to back up everything with Clonezilla Live and then proceed with the 13.2 update. Worse comes to worst I will restore 13.1 and come back here crying for more help…
Yes indeed, and well spotted re not an upgrade but clean install! It seems long ago now, 12.3 with btrfs was a clean install for me. After that several online upgrades have gone smoothly.
Conversion from an existing ext4 can be done with “btrfs-convert”, requiring superuser privilege. There is a “man” page available for the command. There is an option “-r” to roll back to ext2fs if necessary, here is a link to see that: https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-convert
However, it seems there are special considerations when applying it to a root file system, not covered in the man page, such as booting from an install CD/DVD, possibly a Rescue/liveCD/DVD, in order to run it, and use of chroot. Here is an example from the Arch Wiki for Btrfs, under the heading Convert from Ext3/4: https://wiki.archlinux.org/index.php/Btrfs
Not having tried it myself, that is all I can offer, although there will be other links from a google. 
Simply, Yes.
Now THIS is what I like to see!
Someone thinking ahead, thinking practically, and BACKING UP FIRST.
On 2014-11-18 01:16, tb75252 wrote:
> consused;2677106 Wrote:
>> What method are you planning to use for the upgrade?
> I am planning on booting up my PC with the DVD and selecting the Update
> mode, if that option is still offered in v. 13.2.
It is.
> I would then tell
> openSUSE to format the “/” partition, install using the Btrfs filesystem
> and to leave “/home” alone.
No way.
On selecting “upgrade”, no partition is formatted. You have no choice
there, they are left intact, both home and root.
–
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” at Telcontar)
If you are going to reformat root then somethings gotta get wiped