I plan to create two subvolumes on a BTRFS-formatted spinning disk. I plan to mount one of those subvolumes with nodatacow so that I can efficiently store virtual machine images and database files there.
Is there any problem using snapper to enable snapshots of the subvolume mounted with nodatacow?
What should I be aware of when taking snapshots of volumes that don't use COW?
All I have found so far is a sentence in the BTRFS FAQ:
Can copy-on-write be turned off for data blocks?
Yes, there are several ways how to do that.
Disable it by mounting with nodatacow. This implies nodatasum as well. COW may still happen if a snapshot is taken.