rsync takes long pauses in xfer ?

[Alan McKay]

Hey folks,

I did some googling on this but did not come up with much.  I'm using
rsnapshot which uses rsync, and I notice some pretty long pauses in
the xfers as you can see on this graph from "munin".   THe machine in
question right at the moment is doing nothing but rsyncing (
rsnapshoting ) some 12T of NAS storage to local disk, so there is
nothing else going on at all.

https://plus.google.com/u/0/photos/113518077816006248932/albums/5732421463318682369/5753139625064539250

You can see a couple of spots in the graph where it just drops to
nothing ( checking more closely you do see a very small bit of
activity )

Here is another graph from MRTG which records the traffic from the
switch port side.  You can see around 2am it drops off pretty low,
then from about 4am til about 7am it drops even lower.

https://plus.google.com/u/0/photos/113518077816006248932/albums/5732421463318682369/5753140504922328322

Is that normal?  Or is this something I should ask on the rsnapshot
list (if there is one)?

I did find something in google about depending on the types of files
it can change xfer rate but not much detail.

thanks,
-Alan