If I make three partitions on a HDD, it appears that the default (which is -m raid1) will only store two copies of each metadata block.  Is there a way to store multiple copies, e.g. one on each partition where I made as many partitions as I wanted for the purpose?I'm thinking of using this for off-line drives used to hold backups.
Formatting btrfs for robust metadata
filesystems;backup;btrfs