Live Migration is the process of moving a virtual machine (VM) from one Hyper-V virtualization host to another Hyper-V host without any perceived downtime of the VM being moved.
In Windows 2008 R2 Live Migration required a common storage between the source and destination Hyper-V hosts. This shared storage could be an iSCSI LUN, direct attached storage (DAS), or another type of storage, as long as both Hyper-V servers saw the location as a permanent drive (no network drives, or SMB shares).
In Windows Server 2012 this restriction goes away and allows us to migrate virtual machines from one Hyper-V host to another without the requirement of the storage being shared between the hosts. Hyper-V accomplishes this by starting off with a quick migration (see my prior post Introducing Quick Migration), but instead of coming down for the transfer of the active memory, this is transferred in small batches of differencing data until the amount needed to transfer can be done without any perceived downtime. This is a truly remarkable technology, and one that is very welcome in my datacenter.
As with Windows Server 2008 R2, there are some requirements of Live Migration. First off, the VM’s virtual network must be configured on both the source and destination hosts. The second requirement is that the source and destination hosts are using the same CPU brand. So no Live Migrations from an AMD system to an Intel system.
With these changes, Live Migration becomes even more useful than ever before, doing the jobs of both Quick Migration and Live Migration in Windows Server 2008 R2. The new Shared Nothing Live Migration is one more good reason to make the move to Windows Server 2012.
- Windows Server 2012 Feature: Storage Spaces
- Windows Server 2012 New Feature: Hyper-V Replica for Failover
- Windows Server 2012 New Feature: Large Disk Support for Hyper-V
- Windows Server 2012 R2 (Blue) Preview Available for Download