High Performance SSH/SCP - HPN-SSH

Pádraig Brady P at draigBrady.com
Thu Jul 12 15:10:13 UTC 2007


Farkas Levente wrote:
> hi,
> is there any plan to include High Performance SSH/SCP - HPN-SSH into
> fedora's ssh?
> http://www.psc.edu/networking/projects/hpn-ssh/

I noticed that for scp if you disable compression (yes disable),
then transfer rate increases a lot. I looked at it very quickly
and it seemed worse the more the data compressed.
Also Protocol=1 seems much better:

dd bs=1M count=50 if=/dev/zero of=50MB_zeros
dd bs=1M count=50 if=/dev/urandom of=50MB_random

$ scp localhost:50MB_random /tmp
50MB_random                                   100%   50MB  10.0MB/s   00:05

$ scp -C localhost:50MB_random /tmp
50MB_random                                   100%   50MB   4.6MB/s   00:11

$ scp -C localhost:50MB_zeros /tmp
50MB_zeros                                    100%   50MB   2.3MB/s   00:22

#setting Protocol=1 in sshd_config I get the following speed:
$ scp -C localhost:50MB_zeros /tmp #Includes time to type password!
50MB_zeros                                    100%   50MB  12.5MB/s   00:04



When talking about improvements	to ssh, chrootssh seems useful:
http://chrootssh.sourceforge.net/

Also upstream openssh breaks X forwarding in interesting ways
unless -Y is specified (at least fedora fixes this).

Also scp does full remote login etc.
even if local specified files don't exist

Also scp has weird error messages:
$ scp /etc/fstab localhost:/non_existent/
scp: /non_existent/: Is a directory


Don't get me started...

Pádraig.




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