I created a RAID1 mirror but I forgot to add the label. As a result, is it is showing Label: none.
$btrfs filesystem show Label: none uuid: f656414a-3e5c-4ae7-8987-db0eefb6a295 Total devices 2 FS bytes used 128.00KiB devid 1 size 2.50GiB used 520.00MiB path /dev/sdg devid 2 size 2.50GiB used 520.00MiB path /dev/sdh
Now, to add label, I run the following command.
# btrfs filesystem label [<device>|<mount_point>] [<newlabel>] btrfs filesystem label /dev/sdh MyMirrorDisks
For the device, pick 1 of the devices.
The end results look like the followings.
$btrfs filesystem show Label: 'MyMirrorDisks' uuid: f656414a-3e5c-4ae7-8987-db0eefb6a295 Total devices 2 FS bytes used 128.00KiB devid 1 size 2.50GiB used 520.00MiB path /dev/sdg devid 2 size 2.50GiB used 520.00MiB path /dev/sdh