For most Microsoft shops you need SMB3 if you want to use Hyper-V
SMB 3.0 also introduces several security enhancements, such as end-to-end encryption and a new AES based signing algorithm.
Amongst the various new features available in SMB3 that enable enterprise level functionality the key features are:
Support for server-based workloads, including Microsoft Hyper-V and SQL Server.
SMB Transparent Failover. This feature is similar to the functionality provided by Multipath I/O (MPIO) for iSCSI and Fibre Channel networks.
SMB Multichannel – Aggreates bandwidth from multiple links and increases throughput. Also, provides fault tolerance
SMB Direct – Ability to support network adaptors with RDMA.
SMB Scale Out – Provides simultaneous access to files across all nodes in a multi-node cluster.
SMB Performance Counters – Provides conters to track file share utilisation and cover botht he client as well as the server. It helps in troubleshooting performance issues.
SMB Encryption – Allows data travelling between client and server to be encrypted across the network. it only works when both the server and the client are on SMB 3.0 and does not support SMB 2.0 or SMB 1.0