Hyper-V Guess connect to Storage Server - Slow file transfer

Hi,

I am configuring a new File Server. This time we want to use VM.

By using iSCSI, the VM have a d:\drive which is from the HP StoreEasy Storage Server 2012. The d:\drive size is 2TB.

By using robocopy I have transferred files from the old server to the new VM FileServer (d:\drive).

The file transfer is very slow.

But if I transfer files from the old server directly to the HP StoreEasy it will be fast.

I am not sure what to do now

Thanks

Abu.