I wanted to transfer 10TB data from EMC VNX to NetApp FAS storage. Can I use two HBAs on the same server for each storage, and use robcopy to transfer data from one to the other? and also install Host Utility for two different purpose of HBAs? In general what speed would look like for 8Gbits HBAs?
You can of course connect HBAs to two different storage systems from different vendors.
From my experience, what will cause trouble, however, is if you're using management tools, snapshot integration drivers (VSS) or host settings tools from both vendors, as these will generally overwrite each other's settings and get confused easily. for example, SnapDrive might try to snapshot LUNs on 3rd party LUNs and report strange errors.
If you're just connecting these storages for data migration purposes, or are not using any integration tools, you should be fine though.
You are right, there *should* be no problems. But fact is, storage vendors usually don't test these scenarios (where a storage array from a different vendor is connected to the same path/fabric)
Normally it should work but if it doesn't, the problems can be very subtle and only manifest in certain specific configurations. We had an issue once where everything seemed to work fine a tfirst, but if you wanted to trigger a storage snapshot on the NetApp you would get hundreds of errors in the event log, and on at least one occasion the machine even bluescreened.
So while it should work, and probably will work for a while, you should be on the lookout for subtle problems...