Support for transferring sparse files via scp/sftp correctly?

[Mitchell Dorrell]

On Tue, Mar 4, 2025, 05:59 Lionel Cons <lionelcons1972 at gmail.com> wrote:

> On Tue, 4 Mar 2025 at 11:34, Philipp Marek <philipp at marek.priv.at> wrote:
> >
> > > Does OpenSSH scp/sftp mode transfer sparse files correctly, i.e. are
> > > holes skipped and not transferred as chunks of 0 bytes? [1]
> > >
> > > We're asking about sparse files in the >= 1PB range, which consists of
> > > multi-TB holes with around 600-2000GB of valid data.
> >
> > Perhaps rsync would be a good fit here,
> > it supports --sparse.
>
> No, if we would use external tools then mounting NFSv4.2 filesystem
> via
> https://github.com/kofemann/ms-nfs41-client/blob/master/cygwin/utils/sshnfs/sshnfs.ksh
> would be the tool of choice.
>

Would an external tool be useful if it's already present? Most modern
versions of tar can efficiently pack and unpack sparse files (with the
appropriate command line option). If it matters, I'd check whether BSD tar
and GNU tar are compatible when encoding sparse files, though.

-MD

>