About rsync over SSH and compression

[Darren Tucker]

On Wed, 26 Jun 2019 at 02:50, JCA <1.41421 at gmail.com> wrote:
> Thanks; I did not think of that. I have just run a few basic tests with
> both rsync and OpenSSH in their default settings, when it comes to
> compression. SSH compression seems to have a very slight edge.

OpenSSH does not allow you to set the zlib compression level for SSH2
(the protocol spec does not have a mechanism for doing so, although
it'd be possible to add it as a non-standard hack) and OpenSSH
hardcodes it to 6.  In rsync you can crank it up to --compress-level=9
which I'd expect to make it beat any theoretical advantage SSH might
have on compressible data, plus it can be smarter about skipping
already-compressed file types.

That said, I'll second what Stuart said that what matters is what
works best for your data set and environment.

-- 
Darren Tucker (dtucker at dtucker.net)
GPG key 11EAA6FA / A86E 3E07 5B19 5880 E860  37F4 9357 ECEF 11EA A6FA (new)
    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.