Ext4 から Btrfs に移行

その時の手順と状況の記録

前提 (移行以前)

code:sh

$ lsblk

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS

nvme0n1 259:0 0 476.9G 0 disk

├─nvme0n1p1 259:1 0 512M 0 part /boot

└─nvme0n1p2 259:2 0 476.4G 0 part

└─vg0 254:0 0 476.4G 0 crypt

└─vg0-root 254:2 0 460.4G 0 lvm /

code:sh

$ cat /etc/fstab

# Static information about the filesystems.

# See fstab(5) for details.

# <file system> <dir> <type> <options> <dump> <pass>

# /dev/mapper/vg0-root

UUID=4bb9de44-b061-466d-b6ce-fd3b9ae7ef37 / ext4 rw,relatime 0 1

# /dev/nvme0n1p1 LABEL=ESP

UUID=9F92-B431 /boot vfat rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro 0 2

# /dev/mapper/vg0-swap

UUID=e4ecaaa7-cea6-4aea-b538-85817957795b none swap defaults 0 0

手順

# cryptsetup open --type luks /dev/nvme0n1p2 vg0

# btrfs-convert /dev/mapper/vg0-root

code:sh

# <file system> <dir> <type> <options> <dump> <pass>

# /dev/mapper/vg0-root

UUID=a0bb3c42-0485-4367-90dd-5be4956344d3 / btrfs rw,relatime 0 0

# arch-chroot /dev/mapper/vg0-root

# mkinitcpio -p linux

# btrfs subvolume delete /ext2_saved

# btrfs balance start /

code:sh

ERROR: error during balancing '/': Input/output error

There may be more info in syslog - try dmesg | tail`

エラーで失敗する

# btrfs filesystem defragment -r -v -czstd /

(追記：2023/05/21 18:34)

code:sh

$ sudo btrfs subvolume list /

ID 258 gen 18064 top level 5 path var/lib/portables

ID 259 gen 18064 top level 5 path var/lib/machines

参考