I am trying to use RSync to speed up a nightly get of around 3 gigs of data from the east coast to the west over a VPN. I have around 10Mbits of bandwidth between the two locations at a latency of around 110ms to the server. The problem I have is that I can't get the transfer rate to exceed 70kByte/s. If I do a raw Windows copy, I can get 220kB/s, so this seems really low. I have tried turning on compression, running a TCP/IP optimizer on the server (the client is Vista, which claims not to need this), switching to DeltaCopy, and removing the network share (it was copying from a network drive at the server location, now it's direct local drive). None of these had any impact on transfer speed.
I am seeing reduced overall bandwidth usage (rsync cuts 50% of the data transfer), but it's 3x slower, so it's not a net gain. Both machines are very fast (quad core, 10k drives). Both cpus are idling at <1% used by rsync. It seems like it has to be a network issue, but I can't find anything in Rsync to tweak that.
Thoughts? Did I miss something in trying to get this transfer to go faster?