[2023/11]
ZFS is an amazing well-designed file-system with more capabilities than any other.
cp
command will automatically create a COW copy (no special args needed).
Currently (FreeBSD-14.0) ZFS block-cloning feature
must be enabled by putting vfs.zfs.bclone_enabled=1
to /etc/sysctl.conf
.
*** CAUTION: BLOCK-CLONING FEATURE IS EXPERIMENTAL [FreeBSD-14.0] -- MIGHT DESTROY YOUR DATA!!! ***
mv
command will really do expensive copy/delete across ZFS datasets.