Where is my bottleneck?
cedric at cadence.thinkers.org
Thu Mar 11 16:30:37 GMT 2004
On Thu, 11 Mar 2004, Marc Abel wrote:
> Thanks to all three for your kindness. Invoked as:
> rsync -lave ssh --delete --delete-excluded \
> --exclude ".[!.]*" \
> /home/me me at majority:composite_bu
> I did some looking around, and it seems like I haven't even installed
> the daemons for rsh, telnet, etc. (I'll follow up on this, but I can't
> this morning.) Likewise, running the straight rsync-to-rsync connection
> is proving to need a little studying up.
> I really did mean to say 2 Mbit/s. About 10 Mbyte/min is all that I'm
> getting. I can understand ssh slowing things down a lot, but not
> without seeing it get a lot of CPU time. These are 1 GHz machines,
> roughly, and they aren't getting slowed down.
There is an interesting note on SSH cryptographic speeds here:
It shows how to get a benchmark on how quickly the different cyphers
perform, and between that, and sending a known amount of data over
an SSH channel, you should be able to quickly discover if a different
cypher might make a difference.
Here's something that might help to roughly benchmark SSH "raw"
with different cyphers:
bash-2.05b$ time cat /path_to_big_sample_file | \
ssh -c blowfish cadence.thinkers.org "cat - > /tmp/ssh_test_out"
Values for "-c", as far as I know, are: blowfish|3des|des
(This is from OpenSSH 3.7.1)
| CCj/ClearLine - Unix/NT Administration and TCP/IP Network Services
| 118 Louisa Street, Kitchener, Ontario, N2H 5M3, 519-741-2157
Cedric Puddy, IS Director cedric at thinkers.org
PGP Key Available at: http://www.thinkers.org/cedric
More information about the rsync