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<p class="MsoNormal">I thought rsync, would calculate checksums of large files
that have changed timestamps or filesizes, and send only the chunks which
changed. Is this not correct? My goal is to come up with a
reasonable (fast and efficient) way for me to daily incrementally backup my
Parallels virtual machine (a directory structure containing mostly small files,
and one 20G file)</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">I’m on OSX 10.5, using rsync 2.6.9, and the destination
machine has the same versions. I configured ssh keys, and this is my
result:</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">(Initial sync)</p>
<p class="MsoNormal">time rsync -a --delete MyVirtualMachine/
myserver:MyVirtualMachine/</p>
<p class="MsoNormal"> 20G</p>
<p class="MsoNormal"> ~30minutes</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">(Second time I ran it, with no changes to the VM)</p>
<p class="MsoNormal">time rsync -a --delete MyVirtualMachine/
myserver:MyVirtualMachine/</p>
<p class="MsoNormal"> 2
seconds</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">(Then I made some minor changes inside the VM, and I want to
send just the changed blocks)</p>
<p class="MsoNormal">time rsync -a --delete MyVirtualMachine/
myserver:MyVirtualMachine/</p>
<p class="MsoNormal"> After
waiting 50 minutes, I cancelled the job.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Why does it take longer the 3<sup>rd</sup> time I run
it? Shouldn’t the performance always be *<b>at least</b>* as good
as the initial sync?</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Thanks for any help…</p>
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