>look up comparisons on single-disk ZFS vs single-disk BTRFS
>someone said that both BTRFS and ZFS save 2 copies of metadata, but only ever read evidence of it being a thing on ZFS
>look through the 'copies=2' examples of ZFS, leading to discovering the of equivalent as DUP mode on BTRFS
>DUP just specifies 2 data blocks and 2 metadata blocks
>the default settings on BTRFS was in fact 1 data 2 meta