Speed problem

Paul Faure paul at faure.ca
Mon Nov 11 20:54:00 EST 2002

On Mon, 11 Nov 2002, jw schultz wrote:

> On Mon, Nov 11, 2002 at 04:30:05PM +0100, uwp at dicke-aersche.de wrote:
> > Mermgfurt !
> >
> > I have some problem with syncing two machines which are connected
> > over a Gigabit-connection. I'm trying to use rsync with ssh because of
> > the authorisation mechanisms (keys). It starts quite ok with 18 MB/s
> > (this small speed may have something to do with our internal net)
> > and falls down to 400 KB/s (!!!). This happens over a long period
> > because those files I want to copy are very big (upto 70 GB per file).
> > Even though I tried to increase the blocking size the speed just goes
> > down and won't go up again. In fact it really writes 18 MB/s, it's not
> > just a problem of -partial or something similar. Ok, I haven't tried
> > it without ssh yet, but it really looks very strange.
> > The version is the rsync 2.5.6cvs version from debian-unstable.
> >
> > Thanks for any help !

Try it without ssh.

ssh may be waiting in the random pool for more entropy (randomness).
When it grabs a lot of random data, it must wait for more "random" things
to happen to populate the random pool, if it did not do this, your random
data would be predictable and thus insecure.

Try `ls -R /*` on your system when it slows down.

Paul N. Faure BEng				613.266.3286
Carleton University Systems Eng                 paul-at-faure-dot-ca
Chief Technical Officer, CertainKey Inc.        paul-at-certainkey-dot-com

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