I'm having a difficult time breaking 23-36MB/s in my vmware setup. I have ESXi 5.0, and vCenter 5.0 configured. My guest VM's are server 2008 systems with 4-16 cores, per vm. I have 48 cores available, 8gb FC connections to an EMC array, and I'm never over subscribed. When I try to copy files between VM's on the same host with vmxnet3 virtual cards, my connection is 10gb/s, however I have difficulty copying large (100-300GB) files from one machine to the other. Since both machines exist on the same host my communications should be running at bus speeds, but during the file transfer a single processor maxes out and speeds lag at 23-36MB/s. Enabling / setting a buffer value seems to help slightly. Typically around 33-36MB/s but not enough. I've checked / enabled disabled all of the offload, and onload settings, with no success. Any one else have this issue?
Check if these KB articles helps:
And you might check the load on your storage array too.