Besides what the other post said, what have you tried?
Try reading up on the 'netdiag' and 'ifstat' commands on your NetApp.
How long is the WAN connection? ... in milliseconds... The TCP window size for SMB 1.0 typically very small, so high-latency links will suffer a lot more. You can manipulate the filer side with the option cifs.tcp_window_size (17520 is the default) but I am not sure it is going to help or not. SMB 1.0 is just broken. Read up on calculating window sizes for TCP connections. YMMV.
Check your switchports if you are seeing collisions in the ifstat output.
By the way, 7MB/s is still over 55Mbit/s, so you aren't doing too badly if the link is shared with other traffic.
The FAS is already set to SMB 2.0 and the clients I'm testing from are Windows 7 and 2k8R2. cifs sessions command confirms the active sessions are running via SMB2.
Wan link is ~10ms so no issues with latency.
Have checked ifstat on the FAS interfaces and they show zero collisions.
netdiag pops a couple of warnings about NFS TCP packet sizes being slightly off (these are on seperate interfaces to CIFS though) I'll take a look at fixing these in the meantime.
To clarify, I'm more than happy with the general 7MB/sec performance, it's just uploading from SITE B to A that is the issue. It refuses to transfer to the FAS faster than about 1.75MB/sec, as if its capped somehow, whereas uploading to 2k8 servers in SITE A is fine.
Checked routing and it all seems to be fine.
FTP traffic uploads at the full whack, just seems to be CIFS thats affected.
Any other suggestions welcome, I'll keep plugging away at this.