Add new disk to BTRFS RAID 1 partition and remove failing disk

In this article I explain how to replace a failing disk on the BTRFS file system.

In my case disk SDB was failing so I had to replace it with a new disk.

Check BTRFS file system

btrfs fi show
Label: 'btrfs'  uuid: fc34f7ac-7a8c-4b9a-99af-a6fdbdcd0ac5
        Total devices 2 FS bytes used 2.90TiB
        devid    1 size 3.64TiB used 3.62TiB path /dev/sda
        devid    2 size 3.64TiB used 3.62TiB path /dev/sdb

Mount filesystem in degraded mode

mount -o degraded /dev/sda /mnt/btrfs

Add new disk

btrfs device add -f /dev/sdc /mnt/btrfs

Delete failing disk

btrfs device delete /dev/sdb /mnt/btrfs


btrfs balance start --full-balance /mnt/btrfs