ssh tunneld rsync *extremely* slow

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itefix
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Joined: 01.05.2008 - 21:33
ssh tunneld rsync *extremely* slow

Hi,
I set up a ssh tunneled connection between two Win XP boxes. Everything works perfect, except for the speed over the ssh tunnel.

I simply copy a complete folder which contains ~500 MB of data (and, of course, empty the destination between the tests ;-).

Copying the whole folder using a Win share takes ~55 seconds.

Running rsync unencrypted (i.e. without the ssh tunnel) takes ~105 seconds, which is acceptable.

Running rsync over the ssh tunnel (sechaw), it needs 12 *minutes*, which is completely unacceptable. During the transfer, the Win task manager shows a very small system load (less than 5%, sshd and rsyncd both ~2%) and the network load is approx. 5 to 7%.

I repeated the test syncing to a linux box running Fedora Core 3 which has a much slower cpu: here the process took 7:15 minutes, which is still bad but surprisingly much faster than Win.

This might be an indication that the ssh implementation coming with cwRsync is somehow broken. Or are there any other hints how I could speed up the process?

Tia, Cheers,

Albrecht.

itefix
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Last seen: 54 min 19 sec ago
Joined: 01.05.2008 - 21:33
Re: ssh tunneld rsync *extremely* slow

You get a speed penalty because of cygwin emulation layer (30% is mentioned).

You can turn openssh compression off at server side if you transfer your files on a high-speed network. Choosing a less resource intensive encryption can also help. However, this feature is not available in sechaw at the moment. Next version will allow to specify your own tunnel command.

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