Local disk rsync

Tony Abernethy tony at servacorp.com
Fri Apr 10 18:39:07 GMT 2009

listserv.traffic at sloop.net wrote:
> I've done quite a bit of looking, but I haven't found an answer that
> answers this question.
> Environment:
> cygwin on Windows
> rsync 3.0.4
> I know that rsync isn't optimzed for speed on local copies - that's
> clear in my testing. I'm attemting to sync a large volume of files.
> (In this case, I'm syncing a rdiff-backup set...)
> An initial sync will be about one fourth as fast a a cp of the same
> files. "Ok, that's not a huge deal. Subsequent syncs should be a lot
> faster" I though.
> No.
> Using a native windows sync tool, a sync of the source to the
> destination takes perhaps 5 minutes. (~24G, 80K files) However using
> rsync takes a very long time. (I've never let it finish, but it's
> still running an hour later or more...)
> Here's how I run it:
> rsync --recursive --delete --verbose --stats --perms --super
> /cygdrive/e/somedir/ /cygdrive/f/somedir/
> Thoughts?
Any copying, local, from and to the same spindle looks like;

read some stuff
seek to the other place
write some stuff
seek to the other place

Timing should be dominated by how much stuff in each place before it seeks
to the new place.
For Windows, ROBOCOPY may do what you want  (Resource kit XP and below,
native on Vista)
You will probably want the switches /R:1 and /W:1 or similare.

> I'm mainly using rsync 'cause I know it, and use it. If there's some
> alternative I'd be glad for a pointer. I don't know of any other good
> sync tools like rsync. (Unison I guess...though I only need one way
> sync.) [Whole file copy is fine if needed, though some of the files
> are large 1 GB+ and a delta copy would speed these up...]

Why do you think I use Linux ;=)
Cygwin is an incredible program. It almost makes Windows useable. Kinda like
a very bad unix.

Opinions are my own and not necessarily representative of anyone sane.

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