Re: [gentoo-dev] rfc: usrmerge script

[William Hubbs]

On Wed, Mar 24, 2021 at 01:09:52PM -0400, Rich Freeman wrote:
> On Wed, Mar 24, 2021 at 11:09 AM William Hubbs <williamh@g.o> 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.

I'm using busybox, and I just checked and it also supports the
--reflink=auto switch.

I thought about coreutils, but with everything on the fs being moved
around, I think that would get messy.

Thanks a lot for the info Rich. :-)

William

>
> --
> Rich
>