rsync performance degradation? Could be a windows issue?

Greg Freemyer
Mon Apr 11 23:08:00 GMT 2016

On Mon, Apr 11, 2016 at 2:20 PM, Greg Freemyer <> wrote:
> As I test, I just copied 30 GB of 1.5 GB files via robocopy.  None of
> the files had been accessed since a reboot, so none should have been
> in cache.
> According to Resource Monitor, yes.
> I'm getting about 105 MB/sec for read and 105 MB/sec for write vs  70
> MB/sec for rsync.

I just moved both drives to a Linux box.  Using the same rsync command
I'm getting 85 - 90 MB/sec.

That linux box is a 5-year old laptop, where as the windows box is a
pretty beefy box.  (6 cores, 64 GB ram)   Clearly the WIndows box
should be better performing and when running robocopy it is.

So it seems something about the combination of a Windows kernel,
cygwin, and rsync is dropping my performance at least a factor 20% and
maybe as much as 35%.

If I were to run rsync in strace, would anyone want to try and work on
the performance issue?  Or should it just be chalked up to rsync being
optimized for a linux kernel?

Greg Freemyer

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