installation fails on btrfs root partition (multiple-device)

[Miroslav Spehar]

two drives in latitude e7440 -> idea is to split each drive into 3 paritions 1gb, 25gb and rest (~90gb). two 25gb partitions would be made into one 50gb btrfs stripe filesystem and used as root. two ~90gb partitions would be made into a 180gb btrfs stripe filesystem and used as home.

partitions were made manually using fdisk. btrfs was also made manually. ubiquity was then used only to select to which parition those should be mounted to.

details below:

ubuntu@ubuntu:~$ sudo fdisk -l /dev/sda
Disk /dev/sda: 119.2 GiB, 128035676160 bytes, 250069680 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 9E6AAECF-AD43-924D-AB16-1277434C966A

Device Start End Sectors Size Type
/dev/sda1 2048 2099199 2097152 1G EFI System
/dev/sda2 2099200 54527999 52428800 25G Linux filesystem
/dev/sda3 54528000 250069646 195541647 93.2G Linux filesystem

ubuntu@ubuntu:~$ sudo fdisk -l /dev/sdb
Disk /dev/sdb: 119.2 GiB, 128035676160 bytes, 250069680 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 84039022-7032-F24C-A7BA-79A078262C10

Device Start End Sectors Size Type
/dev/sdb1 2048 2099199 2097152 1G Linux filesystem
/dev/sdb2 2099200 54527999 52428800 25G Linux filesystem
/dev/sdb3 54528000 250069646 195541647 93.2G Linux filesystem

ubuntu@ubuntu:~$ sudo btrfs filesystem show
Label: none uuid: 239e7ebd-bdb5-4434-9495-876c626f3137
 Total devices 2 FS bytes used 6.13GiB
 devid 1 size 25.00GiB used 5.01GiB path /dev/sda2
 devid 2 size 25.00GiB used 5.01GiB path /dev/sdb2

Label: none uuid: e6e0e6ea-39d9-43a3-940c-30f33a12a881
 Total devices 2 FS bytes used 916.00KiB
 devid 1 size 93.24GiB used 2.01GiB path /dev/sda3
 devid 2 size 93.24GiB used 2.01GiB path /dev/sdb3

ubuntu@ubuntu:~$

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: ubiquity 18.10.12
ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12
Uname: Linux 4.18.0-10-generic x86_64
ApportVersion: 2.20.10-0ubuntu13
Architecture: amd64
CasperVersion: 1.399
Date: Mon Dec 17 19:48:05 2018
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash ---
LiveMediaBuild: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3)
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)