which #filesystems support #reflinks: on #Linux, Bcachefs, btrfs, XFS, OCFS2, but not OpenZFS; on FreeBSD, neither OpenZFS nor #ZFS; on Solaris, ZFS (with cp -z); on MacOS, APFS (which Apple is switching to; with cp -c or the clonefile system call), and on Microsoft Windows, NTFS and DUPLICATE_EXTENTS_TO_FILE.
The #XFS #filesystem on #Linux has supported #reflinks since about 02016 (XFS 4.9), and btrfs for longer.
on 02021-11-11"reflinks" allow you to make a copy-on-write link to a file snapshot; now supported both on #Linux (cp --reflink) and #MacOS (cp -c). Not supported by ext4fs I think. #filesystem