Windows Server Migration
Coming Soon: Shared-Nothing Live Migration
It almost makes the Hyper-V 3.0 feature of the newly named Windows Server 2012 and System Center Configuration Manager 2012 sound like a selfish only-child. Shared-Nothing Live Migration does not indicate an unwillingness to share. Rather, it provides the ability to move a virtual machine (VM) from one host to another, while running, without the need for the origin and destination servers to share common storage.
While demonstrating it at the recent Microsoft Management Summit 2012, Microsoft Principal Product Manager Jeff Woolsey, introducing the new feature along with Microsoft Corporate Vice President Brad Anderson, held up a simple Ethernet cable, signifying that this was all that was needed to perform a shared-nothing live migration. The VM virtual disks, snapshots and configuration metadata are all moved from one server to another over a simple Ethernet connection. Then the VM state and memory are moved, and finally the VM state on the original host is deleted upon the successful completion of the live migration to the destination host.
Previously, to migrate data from one host to another both had to have a simultaneous connection to a shared storage device that could help by buffering data as it passed between hosts. Shared-nothing means the hosts need to share nothing but a simple Ethernet connection to each other.
As with any new feature introduction, many concerns are already being raised. Since there is no buffering media to establish a recovery point, this solution cannot support a high-availability (HA) strategy. More to the point, many technologists will want to understand what happens when a shared-nothing live migration is interrupted. How will Microsoft avoid corruption of the data, metadata, states and the rest?
Another set of concerns surrounds whether or not the availability of this strategy will help to reduce or will actually increase the gluttonous growth and expense of storage capacity.
Many exciting announcements have been made at MMS, this among the most exciting. It will be interesting to see how Microsoft responds to the analysts during rollouts of Windows Server 2012, System Center 2012, and Hyper-V 3.0.