You can configure the Virtual Server Agent to backup up using different methods, the main two being LAN and SAN.
LAN being obvious and using the network.
SAN is the quickest, and will backup direct from the VM Datastore, for this to work the LUNS need to be present to the Proxy Machine.
Generally you will need 1 VSA per 50 Virtual Machines.
I would normally setup a stand alone proxy machine, LUNS presented to it, Backed up using SAN.
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