If the database resides on a Btrfs file system, you should consider disabling Copy-on-Write for the directory before creating any database.

Source: https://wiki.archlinux.org/title/PostgreSQL

Reference

• https://www.linux.com/learn/how-create-and-manage-btrfs-snapshots-and-rollbacks-linux-part-2
• http://snapper.io/development.html