[xorcist]

There is an attribute called NOCOW that can be set on specific files that should not be copy-on-write, which is what messes with databases, filesystem images and other things that needs fast in-place updates.

It can also be a set as a flag on subvolumes.

[jolmg]

You can also set such an attribute on files and subvolumes in btrfs.

https://wiki.archlinux.org/index.php/Btrfs#Disabling_CoW