* Alexis Gallagher (2004-07-12 19:46 +0200)
I am finding that rsync+ssh is giving extremely slow file transfers. But
this slowdown is hitting not when it needs to send data over the
network, but when it applies the rsync algorithm which is supposed to be
faster than sending all the data over the network. This is very puzzling.
For a benchmark, I tried transfering a 5.4 MB mp3 file three different
ways. Here were my results, as reported by 'scp -v' and 'rsync
--progress --stats':
scp: 311000 B/s
rsync (file not there): 309000 B/s
rsync (file already there): 741 B/s
When the file is alredy there, rsync reports a speedup of about 70.
(When the file is not already there, the speed up is 1, of course.) I am
running rsync over ssh with pre-generated keys installed in my .ssh
directories.
rsync under Cygwin is extremly slow and CPU intensive. For example a
simple script that syncs my dot files from my local NetWare server
takes 1:10 minutes to run and eats about 60% CPU while on my Gentoo
box (which has exactly the same hardware) it takes 7 seconds and 2%
CPU.
Try disabling checksumming, zipping and transfer the whole file
('-W'). Try it without ssh.