I've hit a wall on file transfers between 2 Win S03 SP2 test machines via copy command from a SMB (windows file sharing) share. I can't seem to get faster the 113MB/s
The PC's are directly connected with a 10' factory made Cat6 cable, and all the Disk Volumes can push much more than that.
We've gone through IBM redbook and tried all the optimizations, although most were already active with SP2. The optimizations at the front of the book (up to the reghacks) got us a 50% performance gain.
Jumbo frames and all the reghack's don't show any performance gain, and most show a tiny loss of performance. The same is true with hardware offloading. And the Machines don't seem to be taxed or stresses at all, with little disk activity.
I'm posing this question because Most people see lots of gain from >1500 MTU (Jumbo Frames) and HW offloading. We just aren’t.
Note: yes we know SMB2 can be faster, but were not going to Vista/08/7 in the near future
Here are the PC specs, both are running windows server 2003 Enterprise, both have Intel's new AT2 as their primary nic
GA-x85a-ud9 Main Board
Triple channel DDR3 2200 (6GB) Ram
GA-x852-UD3 rev2 Main Board
Triple channel DDR3 1600 (6GB) Ram
And after an entire weekend of fruitless tweaking we found a Workaround. By using multiple concurrent copy commands, 2 file copied at the same time only takes about ~1/6 longer but twice the data was copied, giving us 182.5MB/s
Three works too, at only ~1/11 longer than two, giving us 253.4MB/s
It was three am and we had to stop, but we're expecting 4 will likewise work.
So we can break 113MB/s with our network but not with a single thread (Copy command).
Has anyone else seen this behavior? or have Suggestions on what is possibly limiting a single thread?