<P> However, with the release of Windows Server 2008 R2, live migration is supported with the use of Cluster Shared Volumes (CSVs). This allows for failover of an individual VM as opposed to the entire host having to failover (it seems that when a node (Hyper - V server, not a VM) fails then each "VM running on the failed node" may migrate to other live nodes independently of "other VMs on the same LUN running on other nodes that share the LUN with the failed node". In Hyper - V we are clustering the Hyper - V nodes not the VMs .). See also Cluster Shared Volumes . </P> <P> Windows Server 2012's implementation of Hyper - V (Version 3.0) introduced many new features to increase VM mobility, including the ability to execute simultaneous live migrations (Windows Server 2008 R2 only supported live migrating a single VM at a time, significantly increasing the time required to carry administrative tasks, such as draining a node for scheduled maintenance). The only real limiting factor here is hardware and network bandwidth available . Windows Server 2012 also supports a new "shared nothing live migration" option, where no traditional shared storage is required in order to complete a migration . Also referred to as "Live System Migration", a shared nothing live migration will move a running VM and its storage from one Hyper - V host to another without any perceived downtime . Live Migration between different host OS versions is not possible, although this is soon to be addressed in Windows Server 2012 R2 . </P> <P> Windows Server 2012 also introduced the ability to use simple SMB shares as a shared storage option (in conjunction with the new Scale out File Services role in Server 2012 for highly available environments), alleviating the need for expensive SANs . This is particularly useful for low budget environments, without the need to sacrifice performance due to the many new improvements to the SMB3 stack . Windows Server 2012 will fully support the live migration of VMs running on SMB shares, whether it be a live or live system migration . </P> <P> Hyper - V under Windows Server 2012 also supports the ability to migrate a running VM's storage, whereby an active Virtual Machines storage can be moved from one infrastructure to another without the VM's workload being affected, further reducing the limitations associated with VM mobility . </P>

What are the basic hardware requirements for windows server 2012/r2 hyper-v