BTRFS Filesystem Dup Your Metadata

BTRFS filesystem owners beware: Linux Kernels <5.14 creates BTRFS filesystems with single-copy metadata only. This is apparently known in BTRFS circles as a huge whoopsie. If you are in the group of users who created your btrfs filesystem using a kernel earlier than 5.14, then you should dup (duplicate) your metadata as soon as possible. You can also enable this feature on existing filesystems without risk to data loss with the instructions below.