VPN slow to copy small files
Posted on 2011-10-21
We have a site to site VPN to a data center that has our web hosting. Our side is a sonicwall NSA 2400 and their side is some sort of Cisco VPN concentrator (I've only got control of one side). We need to transfer sites we develop across this VPN.
Large groups of small files are very slow across the VPN. As an example, I have been using a directory with ~6500 files that is about 32MB. If I copy it as is it takes something north of an hour. If I ZIP it first it takes 2 minutes. The compressed file is about 14MB.
Doing the same file transfers within either network is fast.
We have a 10MB EFM circuit here and I don't know exactly what is at the other side but when I test it we get ~50MB up and down. Latency between locations across the VPN averages about 90ms.
On both sides of the file copy operation we have windows 2008 R2 x64 servers. File transfers to and from the same servers within the LAN go normal speed.
The server on the remote side is a hyper-v guest.
What I have tried with little or no improvement:
Dialing back the encryption from AES-128 to 3Des to possibly reduce that overhead
Uninstalled all AV software on both sides.
Used both robocopy and richcopy with multithreading which helped some
disabled all the TCP offload settings on the test devices
Used FTP instead of windows file copy
disabled the site to site VPN, used the Cisco VPN client instead.
disabled all of the IPS/GAV/Spyware services on the sonicwall firewall
Any ideas here? My developers are not thrilled by the prospect of having to deal with zipping their sites to upload them.