Speed up rsync ,cwRsync and replay changes against a file

[Craig Barratt]

> I recently installed and setup cwRsync on a Windows 2000 Server -
> http://www.itefix.no/cwrsync/ -, and I was very impressed. I just
> followed the instructions on the website and got it working.=20
> 
> I am using it to mirror 30Gb's of mailboxes everynight (only grabbing
> the changes to each file), from a Windows 2000 box to a Linux box (RH9).
> 
> The nightly replication takes approximately 8 hrs to complete, but the
> actual size of the mailbox directory only increases by about 120Mb a
> day. There are 750 mailboxes and each mailbox is between 50 and 200Mb in
> size.
> 
> I am using the following command line options:
> 
> rsync -avz hostname::MailBoxes /mailboxreplica
> 
> Can anyone recommend ways to speed this up - is there some extra
> compression I can use, or a kind of "quick checksum" option that I could
> use?

If you are on a fast network, -z will probably slow you down.

Rsync + cygwin is typically slow due to the system call overhead in
cygwin.  There is a performance patch (patches/craigb-perf.diff)
included with the 2.5.6, 2.5.7 and 2.6.0 releases that makes a
measurable improvement.  This patch is now in CVS.

So you should build rsync from releases sources after applying the
patches/craigb-perf.diff patch (or build from CVS).  Or you can try a
pre-built executable with the patch, like the cygwin-rsyncd package
at http://backuppc.sourceforge.net.

Craig