HPN SSH

Avnish Bhatnagar abhatnagar at mail.arc.nasa.gov
Tue May 8 05:25:42 EST 2007


Hello,

I know this has come up before; but is the HPN patch (or elements thereof)
currently being considered for integration in to the OpenSSH code base?  Are
there pending issues (buffer management, none cipher, etc) which still need
to be addressed?

We have been using HPN-SSH for over a year now, and like others, have
observed significant performance improvement over standard OpenSSH.  I can
scp a 1 GB test file between two HPN-SSH LAN hosts at 700 Mbps (<1 ms
latency).  And over a cross-country high-BDP WAN link, I'm able to achieve
over 500 Mbps (85 ms latency).  These single-stream scp transfers were run
on well-tuned Linux kernels 2.6.15 (or higher) with the arcfour cipher.
(I'll be happy to provide more details about these tests upon request.)  I'm
not sure how 'typical' my results are, but they represent an order of
magnitude improvement over stock OpenSSH.  While the improvement tends to
vary among different platforms, I have never observed a performance
degradation.

We recommend HPN SSH to our users who need to (securely) transfer their bulk
scientific datasets ranging in size of hundreds megabytes to one terabyte;
so naturally, performance is very important for them.  But they (or their
sysadmins) are often reluctant to deploy software which represents a
deviation from a standard distribution...and the maintenance issues that
follow.

Regards,

Avnish Bhatnagar
NASA Ames Research Center





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