BTRFS - lack of subvolume on Ubuntu and Debian?

[Schwarzer Kater]

Did you also test the behavior of Ubuntu 23.04's "Legacy Desktop Installer"? If I understood you correctly you used the new one…
https://ubuntu.com/download/desktop

[jfabernathy]

Did you also test the behavior of Ubuntu 23.04's "Legacy Desktop Installer"? If I understood you correctly you used the new one…
https://ubuntu.com/download/desktop

If you use the legacy installer then the Subvolumes match Kubuntu 23.04. You get @ and @home.

[GreyGeek]

Thanks! You saved me the trouble of a VM install of Ubuntu 23.04 to check its btrfs install.

[claydoh]

The new installer actually uses subiquity under the gui - which is the server installer software.
Not sure if this report is still relevant, or how btrfs is handled on this non-gui tool in a server install.

Surprised at the severe lack of bugs/complaints, even on Reddit

In any case, only Ubuntu users will have this issue, unless the use the 'legacy' iso for Lunar.

[jfabernathy]

Just FYI but I was looking to see if Debian could be blames for this subvol issue. However Debian 12 (Bookworm) RC1 still only creates and mounts one subvolume and it's called '@rootfs'.

So it seems the Ubuntu problem is not related to how Debian is doing it.

[Worzel]

I've done a fresh install of Neon but the option I took, the first of three, went straight into installation with boot/uefi, / ext4, no options, and swap 8.8 gib

Searching turned up info from last year that Neon 'btrfs' install fails because /calamares/desktop/modules/fstab,conf requires the setting "space_cache" has to be changed to "space_cache=v2" but before installation. Difficult when it is fully automated.

[claydoh]

Neon 'btrfs' install fails because /calamares/desktop/modules/fstab,conf requires the setting "space_cache" has to be changed to "space_cache=v2" but before installation. Difficult when it is fully automated.

I thought that they (re)fixed this bug.

Anyway, it is easy enough to edit that config file from a live session before beginning the installation.
The iso should not go straight to an installation, it has always gone to a desktop, and this week's image seems to be no different here.

[Worzel]

First off, apologies to jabernathy for usurping this thread but it was about a BTRFS install.
Second, thanks Claydoh for getting an old sod to so-to-speak RTFM

i only recently found out about space_cache amendment but didn't understand where it was. Now resolved.

Installation usb gave three options "UEFI install PMAP", "UEFI install", or USB. After several attempts with usb and not finding BTRFS available I gave up.
First option "UEFI install PMAP" created boot/efi, ext4 and swap with no action required at all.

I should have used KDE Discuss but....nuff said!

Thanks again, off to reinstall with BTRFS.

[claydoh]

Installation usb gave three options "UEFI install PMAP", "UEFI install", or USB. After several attempts with usb and not finding BTRFS available I gave up.
First option "UEFI install PMAP" created boot/efi, ext4 and swap with no action required at all.

I have no idea what these are, or what they are from. They are definitely not from the ISO image itself. I am guessing they may be from whatever software you use to create the USB install stick?
But a new thread on this is appropriate - we DO have a KDE neon section......

[methanoid]

If you use the legacy installer then the Subvolumes match Kubuntu 23.04. You get @ and @home.

I do hope that the new installer is fixed in this regard BEFORE they remove the Legacy Installer. Luckily I am currently preferring Kubuntu to Ubuntu

[jlittle]

If through some installer lack of features, or misfeatures, a Linux installs to the btrfs root, would it work to create a subvolume for root, say @root, and copy everything into it, then making a /boot/grub/custom.cfg to boot into it?

The custom.cfg would just copy the first menuentry from /boot/grub.grub.cfg, and have the linux and initrd lines changed:

linux /@root/boot/vmlinuz root=UUID=whatever ro rootflags=subvol=@root
initrd /@root/boot/initrd.img
​

It would be good to clean up the /etc/fstab entry for / to have the subvol=@root option, but I presume that's not necessary, because / is already mounted to even see /etc/fstab.