Rsync over NFS mount sending whole files
anbanm at gmail.com
Fri Oct 28 08:45:53 GMT 2005
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
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).
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