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From: Lapo Luchini <lapo AT lapo DOT it>
Subject:  Re: Rsync issues with Windows Server 2008
Date:  Sat, 21 Mar 2009 08:53:39 +0100
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Des Dougan wrote:
>> The application using the
>> databases was also having shutdown issues, so it appeared to be an
>> application-caused hang. Subsequently, though, I am seeing other
>> hang-ups.

Please notice that rsync-over-SSH on Cygwin has an unfortunate known
bug: it sometimes stalls and must be killed. This can happen rarely or
often depending on the person reporting it, and some work has been done
to pinpoint the problem, but it seems to go pretty deep and hasn't been
fixed yet.

A work around that usually works is to avoid SSH and use rsync://
protocol, but of course that means losing all the security advantages of
SSH (though maybe you could use rsync:// on a SSH-tunneled port with
success, using a slightly more complex script).

See also: http://thread.gmane.org/gmane.os.cygwin/77338/focus=77434

> Sorry to reply to my own post. I tried some other options, and found
> that if I used the rsync "W" option instead of the "u" option, the
> backup ran cleanly.
> 
> Can someone clarify why this change affects the process?

The -W option tells rsync to always transfer the whole file instead of
only the changed parts, so it transfers quite more bytes, but it's less
CPU-intensive. On why this works the problem around for you, it's
probably because it changes the use quite a bit and casually doesn't get
into that hang.

-- 
Lapo Luchini - http://lapo.it/

“We do what we must because we can.” (videogame "Portal", 2007)


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