In Windows Server 2012, you can configure a virtual machine so that it is stored on an SMB file share. You can then perform a live migration on this running virtual machine between non-clustered servers running Hyper-V, while the virtual machine’s storage remains on the central SMB share.
This allows users to gain the benefits of virtual machine mobility without having to invest in the clustering infrastructure if they do not need guarantees of availability in their environment. (Hyper-V with SMB storage can also be configured with Failover Clustering if you do require high availability. For information about different configurations of Hyper-V with SMB storage, see Deploy Hyper-V over SMB.)
You can also perform a live migration of a virtual machine between two non-clustered servers running Hyper-V when you are only using local storage for the virtual machine.
This is sometimes referred to as a “shared nothing” live migration. In this case, the virtual machines storage is mirrored to the destination server over the network, and then the virtual machine is migrated, while it continues to run and provide network services. For instructions, see Configure and Use Live Migration on Non-clustered Virtual Machines.
This functionality allows live migration in the most basic deployments and in more advanced scenarios, such as performing a live migration for a virtual machine between multiple, separate clusters to load balance across an entire data center.
Common requirements for any form of live migration:
Requirements for live migration in a cluster:
Requirements for live migration using shared storage:
Requirements for live migration with no shared infrastructure:
See http://technet.microsoft.com/en-us/library/hh831435.aspx for more information :)