It's intriguing that XFS, which lacks the integrity checks that ZFS or BTRFS offer, is the recommended filesystem for databases, even distributed ones like CochroachDB.
I don't have any experience with ZFS, and very little with BTRFS, but the reason I pick XFS is that has "just worked", out of the box, on every Linux distribution I've managed for about 20 years. Back then, it was one of the few choices that didn't have a static inode limit, and it could be grown while mounted. That was a big convenience on file servers when combined with LVM and/or hardware RAID. ZFS sounds hard to manage, I thought BTRFS was still eating peoples' data for a while, and XFS just keeps working fine.
The main log provides CoW-like functionality, & archive logs provide snapshot-like functionality. Having the DB & the file system duel over these responsibilities is trouble waiting to happen.
