On Wed, Mar 24, 2021 at 11:09 AM William Hubbs <willi...@gentoo.org> wrote: > > On Wed, Mar 24, 2021 at 08:48:41AM +0100, Michał Górny wrote: > > > > What really can help is reflinking on filesystems supporting that. > > What really can help is more info instead of being terse like this. > Which filesystems support it? >
According to Google right now: Btrfs, CIFS, NFS 4.2, OCFS2, overlayfs, and XFS Lizardfs ought to, but doesn't currently. zfs does not because clones only are supported at the dataset level. In any case, if you're using coreutils cp to do the copy, just pass --reflink=auto. Honestly, I have no idea why this isn't the default behavior. Who wouldn't want instant copy operations that consume zero space (aside from metdata)? If you're doing this in C or some other language you would need to see if they have a library call to do it easily - see man ioctl_ficlone. -- Rich
