Simple commands to setup a BTRFS filesystem across multiple disks as a JBOD implementation.
# Create a filesystem across the drives (metadata mirrored, linear data allocation)
sudo mkfs.btrfs -f -L MEDIA -d single -m raid1 /dev/mapper/data-*
To show all the filesystems
sudo btrfs filesystem show
To check filesystem usage
sudo btrfs filesystem df /mnt/media
In order to then add a disk to this filesystem later
sudo btrfs device add /dev/sdb /mnt/media
btrfs filesystem balance /mnt/media
We can also convert another btrfs filesystem data allocation (e.g. RAID1) to single
as part of the balance process.
sudo btrfs balance start -dconvert=single,soft /mnt/media
btrfs doesn't have really jbod/linear option afaik. When you do multivolume btrfs with data profile single, it works very similar as you would be using it as raid-0. Distributing data evenly to all available drives, 1GB chunks. So if one drive fails, you end up losing most of the data what is greater than 1GB.