Hello,
I have a poweredge T610 with a 1GB Cache controller in RAID 50 with 6 fast drives. I have the cache policy turned on. If I copy a VHD file on the host from the same volume to the same volume on the host, it copies with an average speed of 700MB/s (starting out around 800 and finishing around 500 keeping at around 750 most of the way).
If I try to copy from the host to a share on a VM (fixed drive 500 GB on the partition - hosted on the same volume that the I got 750MB/s copying from host to the same host) - I get about 75MB/s. If I try to copy from the VM to the host I also get about 75MB/s average. If I turn off the windows firewall (I'm not using any other software firewall on the server) I get about 105MB/s on average. I have the nics on the host and VM in a trunk and I got about the same speed when the Nics were set up as single nics so that didn't change performance much. I tried turning off IPv4 large send offload - no difference. I tried just about every single option in the hyperv nic settings - no significant difference.
The host server and the VM are on the same subnet, on the same switch. It is after hours and there is no backup or any user activity on the network. I've tried Broadcom and intel server nics with the latest firmware and drivers.
Is there some trick to getting better performance/throughput on the VMs?