Mapped Drive

Stephen Zemlicka stevezemlicka at
Fri Sep 28 22:28:58 GMT 2007

Is there a way to have rsync cache the checksums for something like this and
would that help?

Stephen Zemlicka
Integrated Computer Technologies
PH. 608-558-5926
E-Mail stevezemlicka at 

-----Original Message-----
From: hashproduct at [mailto:hashproduct at] On Behalf Of Matt
Sent: Monday, September 24, 2007 6:51 PM
To: Stephen Zemlicka
Cc: rsync at
Subject: Re: Mapped Drive

On 9/24/07, Stephen Zemlicka <stevezemlicka at> wrote:
> I think I got it (with the help of a friend).  You can, in fact, rsync to
> mapped drive efficiently.  You must include --no-whole-file.  My 100MB
> only transferred a few MB using that method and it opened up with the
> changes just fine.  Now it works just like I want.  It's not the quickest
> but definitely quicker than uploading hundreds of MB for each database.

Of course --no-whole-file will make rsync report a smaller number of
"bytes sent", but is it actually reducing the amount of I/O to the
mapped drive?  If so, I find this really surprising.  The one
explanation I can think of is that the network filesystem has cached
the file, so reading the basis file costs nothing and writing only the
changed areas (due to --inplace) is a big saving.  Is this the case?


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