rsync performance question

jw schultz jw at
Fri Jan 9 01:06:16 GMT 2004

On Thu, Jan 08, 2004 at 01:05:25PM -0500, Rick Frerichs wrote:
> Hello,
> I seem to be having a performance problem with rsync.
> I have done some testing of rsync and ftp.  If I do
> a transfer (either way) with ftp, I get about 500 Kbytes/sec.
> Using rsync to do the same transfer (either way) I only get
> about 50 Kbytes/sec.  I am only testing straight file
> copies.  There is a firewall which I believe is configured
> properly.  The ethernet interface is running at 10 Mbit
> full duplex.  Does anyone have an idea of where I should be
> looking to solve this problem?

A mirror :)

Seriously, rsync increases the load on CPU, memory and disk
for the sake of reducing load on the network for
synchronising files and directory trees.  Rsync is less
efficient than most copy utilities at straight copying and
it's performance as a copy utility should not be considered
when evaluating it as a synchronisation utility.

The performance hit you are getting seems greater than i
would normally expect.  It may be rsync is pushing you over
a threshold into a swap storm.  Perhaps you are using some
odd options (-c, -T) that slow things down dramatically.  A
10MbFD network sounds very odd, FD would be switched or on a
crossover 10Mb would be obsolete hardware indicating that
possibly you have a very slow CPU, small memory and slow
disks.  As you provide no information regarding system
configuration, versions or command-line options i can only
speak in generalities.

	J.W. Schultz            Pegasystems Technologies
	email address:		jw at

		Remember Cernan and Schmitt

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