Rsync over NFS mount sending whole files

[Anban Mestry]

Amazing. Connecting to the NFS server directly instead of through a
mount results in much better transfers. Thank you. It looks like just
the updated portions of the files are zoomed across.

A dumb question, but why? Does the rsync daemon on the server side
have anything to do with this? Or does the NFS client act as if the
mount is a "local" directory and tries to do read and writes just as
it would on disk?

Anyways, it works - so I'm happy.

Thanks again for your help
Anban.

On 10/28/05, Wayne Davison <wayned at samba.org> wrote:
> On Thu, Oct 27, 2005 at 07:27:09PM +0200, Anban Mestry wrote:
> > rsync -avtz --no-whole-file \test1\ \mnt\test2\
>
> You don't want to do that, because --no-whole-file optimizes rsync's
> socket I/O at the expense of disk I/O, which means that you're making
> things less efficient when the "connection" between the sender and the
> receiver is a local pipe.  The use of -z for a "local" copy is also
> wasteful because you're using CPU to optimize the transfer of data over
> a connection that is faster than the disk I/O, even when uncompressed.
>
> Your best configuration is to avoid updating via NFS and instead connect
> to the NFS server directly so that rsync can update the files on a local
> disk.  That allows rsync to optimize the network traffic.
>
>     rsync -avtz /test1/ remoteNFShost:/test2/
>
> If that is not possible, the method that uses the least disk I/O for a
> local copy is --whole-file and (to a much smaller extent) --inplace.
> That still writes out the entire file over NFS for each update, though,
> but it does at least avoid having rsync do a full-file read followed by
> a full-file write (which is what occurs with --no-whole-file).
>
> ..wayne..
>


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