I just tried copying a file over cifs (windows file sharing) between a server 2003 R2 and a new server 2008 SP1 and I'm getting horrible speed.
it's a 300MB file that is taking around 30 minutes to transfer. I'm getting around 1-2Mbit/s and this is on a local switch.
I have tried initiating the transfer from both servers with the same results.
Copying from the 2003 to another 2003 is less than 1 min, so it's obviously something with the 2008-server.
An even weirder behaviour is that if I simultaneously copy another file from the 2003 server to another 2003 server, the transfer rate from the 2008 server increases drastically (like 10x times, but still slow though).
Over RDP-drivesharing I get full VPN-speed, approx 20Mbit. No other services seem to be suffering from any latency.
I have seen post about tcp offloading causing trouble in win2008, could it be related?
Best Answer
Make sure the 2008 server is working properly on its own. Try tranferring files betweeen it and another 2008 server, or if one isn't available a vista workstation, they use the same cifs version.
I've seen similar file transfer behavior when there was a speed/duplex mismatch between the NIC and the switch, sometimes because of an autosense problem and sometimes because of a misconfiguraton of one or the other, or both.