subiquity isn't able to create btrfs subvolumes during installation

[Gannet]

I always use my system on two btrfs subvolumes: @ and @home. And it worked until 20.04 came out with no Debian installer but with new unusable subiquity one which is not creates btrfs subvolumes if I chose / as a mount point on btrfs. Instead of it says: "Mounting an existing filesystem at / is usually a bad idea, proceed only with caution" which is quite strange in my case. How should I install 20.04 on btrfs with two subvolumes?

[Michael Hudson-Doyle (mwhudson)]

Yes, this is a gap.

Out of curiosity, would you be OK with supporting ZFS in a similar way as the desktop installer currently does, or do you prefer btrfs for some reason?

[RussianNeuroMancer (russianneuromancer)]

Michael, I guess you perfectly know why people choose ZFS over btrfs, and why other people choose btrfs over ZFS. Lack of proper btrfs support in Ubuntu Server installer wouldn't suddenly make admins switch from btrfs to ZFS - instead they will switch to Debian with familiar behavior.

So in my option right question is not "if btrfs users is Ok with ZFS?" but "for how long btrfs users willing to wait until subiquity implement familiar behavior for installation on btrfs before they will start transition to Debian?"

[Mikhail Novosyolov (mikhailnov)]

+1 for @ and @home by default. No wish to have affairs with ZFS.

[Halvor Lyche Strandvoll (halvors)]

+1 for @ and @home by default.

[Thomas Dreibholz (dreibh)]

+1 for @ and @home by default.

[Tomaz Strukelj (cofkomail)]

You can just move to @ and @home manually after install.
My issue is a different one, Subiquity doesn't support installing on existing btrfs (I have RAID1 setup), it errors out with exit status 3.

My workaround was to
1. install the system on a separate drive
2. manually copy everything to new btrfs subvolumes /@ and /@home
3. make it bootable by booting from live ISO and running:

---
# be careful here, don't set the wrong device
DEVPATH=/dev/sda
DEVPARTPATH=/dev/sda2
MNTPATH=/mnt/sda2
MNTOPTS="-o subvol=@"

mkdir ${MNTPATH}
mount ${MNTOPTS} ${DEVPARTPATH} ${MNTPATH}
mount -t proc none ${MNTPATH}/proc
mount -o bind /dev ${MNTPATH}/dev
mount -o bind /sys ${MNTPATH}/sys

# get into the target system
DEVPATH=${DEVPATH} chroot ${MNTPATH} /bin/bash

# generate Grub2 config grub.cfg
grub-mkconfig

# generate Grub2 menu.lst file
update-grub2

update-initramfs -u -k all

# clean bootloader ; 512 (MBR) = 446 (bootloader) + 64 (part table) + 2 (signature)
dd if=/dev/zero of=$DEVPATH bs=446 count=1

# install Grub2 to MBR
grub-install --recheck $DEVPATH
---

[Gannet (ken20001)]

I can just use windows. But this is not my option. Thanks. A full-fledged installer should support this simple things. Moreover a Debian installer had this support.

BTW Debian installer has not support installation on RAID1/0. And you can just first make an installation on usual partition and then add another one partition to the first one with 'btrfs device add' command and then perform a balancing with 'btrfs filesystem balance start -dconvert=raid1 -mconvert=raid1 /'.

[Anadon (anadon)]

Also seen in https://bugs.launchpad.net/subiquity/+bug/2024957 and https://bugs.launchpad.net/subiquity/+bug/2017893 .

This also breaks Timeshift, which expects subvolumes created for @/ and @/home. See https://github.com/linuxmint/timeshift/issues/232#issuecomment-1718289102 .

[Sebastien Bacher (seb128)]

Closing that ubuntu-desktop-installer report since the component is deprecated. We aren't going to fix 23.10 installer bugs at this point and Noble uses ubuntu-desktop-provision, feel free to reopen/reassign to that component if that's still an issue with the noble beta image

[Jonas Gamao (yamiyukisenpai)]

but it didn't work when I used Noble livecd

[Jonas Gamao (yamiyukisenpai)]

Tested with Noble Ubuntu Server

[Jonas Gamao (yamiyukisenpai)]

created separate one, just in case
https://bugs.launchpad.net/ubuntu/+source/curtin/+bug/2062952

[Dan Bungert (dbungert)]

@Jonas - please don't knowingly create duplicates.

[Jonas Gamao (yamiyukisenpai)]

Sorry. Wasn't sure if that Ubuntu Server was part of it due to"ubuntu-desktop-provision"

[Riccardo Musso (gjman78)]

+1 for @ and @home by default.

[Gannet (ken20001)]

The new installer is worse than the old one. And this bug is 4 years old already.

[Jonas Gamao (yamiyukisenpai)]

Wish the team would take priority in solving this, or at the very least have some way to create custom subvolumes.

I dunno, it’s just tedious when I had to fix mine.

[Gianmarco (gianmarcoesgarix)]

+1 for @ and @home by default.

[Jonas Gamao (yamiyukisenpai)]

Any updates?