Hi Chaos, (Just have to love that name!)
> hi. we are running ssh 2.3.0 from ssh.com on a solaris network with
> mostly 100mbit data connections. i am finding that, even using
> blowfish or twofish (which seem to be the fastest of the included
> algorithms) and enabling compression, transfer speeds are much slower
Simple - just don't use compression. It is a performance killer. You
have enough bandwidth not to require any. It's okay for ISDN... :)
I seem to remember recently having posted quite a lengthy note on this,
but I can't find it now in the archives. Maybe I posted it privately...
At any rate, in our composite 100M Ethernet / 155M ATM network, I can
get up to several MB/s on scp even on old computers without compression...
and with compression it's unlikely I'll even get 1 MB/s, even when both
ends are reasonably fast (750 MHz Athlons running Linux / 500 MHz Alpha
21264A's on Digital UNIX / 440 MHz UltraSPARC IIs running Solaris 7, for
example)
> so i'm curious what can be tweaked in terms of compilation and/or
> configuration options to improve data transfer speeds.
Your first improvement is letting go of compression. Really. You'll be
amazed.
You mentioned you were using Solaris? Compiling on SUNWspro or gcc?
Use "-fast" if SUNWspro. I found that on IRIX, forcing the compiler to
inline all it possibly could resulted in significant improvements over
the normal -O2. (On IRIX, the maximum optimisation to MIPSpro cc, -O3,
breaks something and the binaries no longer work.)
--
Atro Tossavainen (Mr.) / The Institute of Biotechnology at
Systems Analyst, Techno-Amish & / the University of Helsinki, Finland,
+358-9-19158939 UNIX Dinosaur / employs me, but my opinions are my own.
< URL : http : / / www . iki . fi / atro . tossavainen / >
