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True VM mobility 
Being able to move VMs from one host to another has been a must since the inception of Hyper-V. In 
the early days of Hyper-V, during the Windows Server 2008 timeframe, only offline migration was 
possible (see Figure 2-6). The VM was taken offline, moved, and then brought back online. This was 
done by using the export and import functionality. Although this offered some VM mobility, it was 
restrictive in that it required downtime for the VM. 

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CHAPTER 2 | Software-defined datacenter 
Figure 2-6:
Offline migration 
In Windows Server 2008 Hyper-V, you could move a VM from one host to another host only when the 
VM was offline. 
Later, with the release of Windows Server 2008 R2, live migration made it possible for the first time to 
move a VM while it was still running. However, live migration was available only between clustered 
Hyper-V hosts where the VMs lived on a cluster shared volume (CSV), as shown in Figure 2-7. 
Figure 2-7:
Live migration 
Windows Server 2008 R2 Hyper-V introduced the ability to move running VMs from one cluster node 
to another cluster node. 
A completely new level of freedom came with Windows Server 2012 and its ability to live-migrate VMs 
between any Hyper-V hosts of the same version (see Figure 2-8), regardless of whether either the 
source or destination was part of a failover cluster. 
Figure 2-8:
Any host, same OS live migration 
Windows Server 2012 Hyper-V introduced the ability to move running VMs from any host to any 
other host. 

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19 
CHAPTER 2 | Software-defined datacenter 
Windows Server 2012 R2 took live migration a step further, introducing the first "cross version" live 
migration. VMs could live-migrate from any Windows Server 2012 host to any Windows Server 2012 
R2 host, regardless of its membership in a failover cluster (see Figure 2-9). 
Figure 2-9:
2012 to 2012 R2 live migration 
Windows Server 2012 R2 Hyper-V introduced the ability to move running VMs from a host running 
Windows Server 2012 to a host running Windows Server 2012 R2. 
Windows Server 2016 breaks yet another boundary with down-level migration, giving administrators 
true freedom of control over their VMs. Previously, live migration would work only between hosts 
running the same version of Windows Server or the next version of Windows Server. The table that 
follows summarizes the migration options available for Hyper-V in each version of Windows Server 
running on the host: