Aidan Finn, Microsoft Most Valuable Professional (MVP), has been working in IT since 1996. He has worked as a consultant and administrator for the likes of Innofactor Norway, Amdahl DMR, Fujitsu, Barclays and Hypo Real Estate Bank International where...
Now that you can purchase Windows Server 2012 R2 (WS2012 R2), it’s time to consider how you will upgrade to the newest version of Hyper-V. In this article I will discuss a new strategy for upgrading from WS2012 Hyper-V to WS2012 R2 Hyper-V using a new feature called cross-version live migration.
With cross-version live migration you can perform a one-way (no return trips) live migration of virtual machines from WS2012 Hyper-V to WS2012 R2 Hyper-V. The frequently asked questions about cross-version live migration are:
It’s the same answer every time!
There are two ways to use cross-version live migration, each of which leverages a features of live migration from WS2012 Hyper-V.
You can store virtual machines on WS2012 (or later) file servers, including the scalable and continuously available Scale-Out File Server. Changing the possible owners of a virtual machine is basic Windows administration:
Cross-version live migration with SMB 3.0 storage.
There are two notes with regard to live migration to or from a Hyper-V cluster:
Some companies that deployed WS2012 Hyper-V in recent months chose to use SMB 3.0 storage (including SANs that were abstracted by scale-out file servers) for their Hyper-V hosts/clusters, because this option allows a very simple migration to newer hosts with no downtime to service availability. An added benefit of this approach is that there is no need to invest in new storage capacity; the existing investment is retained without expansion because the VM’s files are not being moved – only the ownership of the virtual machines is moved in this process.
Added to WS2012 Hyper-V, shared- othing live migration allows the movement of a virtual machine (as you expect with live migration) as well as the relocation of the virtual machine’s files. When combined with cross-version live migration you get migration options such as the following.
From WS2012 | To WS2012 R2 |
Non-Clustered WS2012 Hyper-V host | Non-Clustered WS2012 R2 Hyper-V host |
Non-Clustered WS2012 Hyper-V host | WS2012 R2 Hyper-V cluster |
WS2012 Hyper-V cluster | WS2012 R2 Hyper-V cluster |
WS2012 Hyper-V cluster | Non-Clustered WS2012 R2 Hyper-V host |
The ability to move the virtual machine’s files means that you can use direct-attached storage (DAS) or internal disk in the source and destination non-clustered Hyper-V hosts. You could also introduce new cluster shared volumes (new SANs or SAN LUNs) when moving to a new WS2012 R2 Hyper-V cluster.
Shared-nothing cross-version live migration.
This option will not be as fast as cross-version live migration with SMB 3.0 storage. The time required depends on several factors, including:
This means that while there is little human involvement in this zero-downtime migration, it might take some time to move lots of virtual machines from WS2012 Hyper-V to WS2012R2 Hyper-V, and that might be an issue if your older infrastructure is not healthy.
There are reasons not to use cross-version live migration. Consider the following:
Those who are considering the following will like cross-version live migration:
Cross-version live migration makes it possible to move your VMs onto WS2012 R2 Hyper-V with no downtime, but your upgrade project is not complete. There are still two steps to perform – one of which is very important and should be done, and the other which should be considered.