Walking out of the keynote at Microsoft’s “Get Virtual Now” event in Bellevue, WA this week, I found myself thinking about how this was the second time that Microsoft has pre-announced that they would have live migration for Hyper-V. (Apparently, I was not the only one — see “Microsoft Backtracks on Live Migration, Again” on internetnews.com.)
For any readers new to virtualization, live migration is the ability to move a running virtual machine (VM) from one physical server to another without the VM end-user experiencing any disruptions. This capability enables IT admins to do things like:
- Perform planned maintenance at anytime (instead of only during evenings, weekends, or maintenance windows),
- Perform anytime dynamic load balancing to meet real-time application demands, and
- Save power by consolidating VMs to fewer servers during non-peak hours.
VMware was the first to deliver live migration in 2003 when we released VMware VMotion. Since then, others have followed VMware’s lead and delivered live migration (such as various Xen-variants in 2007). According to our customers, live migration via VMotion has become an indispensable component of their virtualized production datacenters.
Microsoft Live Migration: Take One
The first time Microsoft pre-announced live migration for Hyper-V was in 2006 when they stated that “Viridian” (codename for Hyper-V back then) would ship with live migration and other capabilities that would surpass VMware ESX. Then in May 2007, Microsoft had to retreat and drop live migration, hot-add memory and CPU, and support for 32 logical cores from Hyper-V 1.0 in order to prevent Hyper-V from slipping further. (Remember, these dropped capabilities were the ones that Microsoft previously touted as reasons Hyper-V would surpass VMware ESX.)
Microsoft Live Migration: Take Two
So now we get the second pre-announcement on live migration which says that live migration will be available in Windows Server 2008 R2. According to what Microsoft had previously told press, R2 is slated for 2010. Onstage Bob Muglia stated something to the effect of “there’s no magic in live migration, it is just a feature…” Well if it is as easy as the statement implies, why doesn’t Microsoft have the functionality now? Why will it take until 2010?
Now you may say, “Yes, Microsoft is late, but I’m ok waiting.” But waiting costs your company real dollars. Look at this simple example: By using VMware VMotion for planned server maintenance in a 150-VM environment you can save almost $60,000 a year in operational costs. If we scaled to a 1000-VM environment, it results in almost $400,000 of cost savings a year. If you use VMotion for more than planned server maintenance, and use it for dynamic load balancing, distributed power management, etc, you’ll save even more!
Live Migration is a Core Virtualization Requirement
To pre-announce live migration – twice – shows that even Microsoft has realized the foundational role that live migration plays in a virtual datacenter. It’s not a “nice-to-have” but a “must-have” capability. Microsoft used to claim that Microsoft Quick Migration was “good enough” because it only caused seconds to minutes of downtime – but that downtime causes interruptions to the end user and that is unacceptable. Microsoft must have gotten enough grief from customers over this claim because I don’t see them saying it as much any more. Anyone who has actually used VMware VMotion knows that you can’t afford the downtime — look at this demonstration of how disruptive the downtime caused by Microsoft Quick Migration is to an end-user.
Assuming no further slips, when Microsoft delivers live migration in 2010, it will be seven years behind VMware (VMotion in 2003). Today, VMware has distinct advantages over Microsoft in our VMware Infrastructure 3 product, such as Storage VMotion, logical resource pools, DRS, and in our Application and Management Infrastructure products, like VMware Lab Manager, Stage Manager, Site Recovery Manager, Lifecycle Manager. By 2010, VMware will extend our leadership even further – keep an eye on announcements coming at VMworld 2008.
Microsoft Did Demo Live Migration, but…
As a technical aside: Microsoft’s live migration demo during Bob Muglia’s keynote felt kinda weird (see for yourself – available in .mpg or .wmv) with what seemed like a streaming video player super-imposed on top of the Cluster Administrator console. During the actual migration, the video was stretched to full screen, obscuring the Cluster Administrator console, and then shrunk back down once the migration was declared as completed. I realize the video was supposed to show that the live migration did not disrupt the playing video, but it wasn’t very convincing since streaming video can be cached. Not sure Microsoft cares what I think, but I have some suggestions to make it a more compelling demo:
- Show an RDP session into the virtual machine being migrated so people can see what happens to someone logged into the virtual machine
- Show a continuous “ping” to the virtual machine being migrated so people can see any downtime of that virtual machine
- Show the management console during the entire migration so people can see what the admin will see
- Show a more complete process of how to initiate a virtual machine live migration, ie. select target host, test for compatibility, etc.
Here’s an example of how we’ve demoed VMotion.