Viridian Features Trimmed – a Little off the Ears? Or Buzz Cut?

Days before one of Microsoft’s largest events, Microsoft WinHEC 2007, the company announced that it was trimming three key features from its hypervisor technology, Microsoft Windows Server Virtualization (codenamed Viridian).

The first feature, and probably the most significant, to be pulled from the initial release of Viridian is Microsoft’s live migration capability which is much akin to what VMware has been selling for years and calls VMotion. The feature is important because it offers the ability to move a virtual machine from one physical host server to another with no perceivable downtime. Besides being an important feature to the end user, having this ability in Viridian would give the hypervisor technology parity with competing products such as VMware, Virtual Iron and XenSource. Or more importantly, not having this specific feature in the initial release of Viridian is probably going to be a huge marketing win for its competitors. Not only does it continue to represent an important product differentiator, it also shows just how difficult the concept of live migration is to implement.

The second feature being pulled is the “hot-add” or “on-the-fly” capabilities which would allow a user to add or swap out processing, memory, networking or storage resources without having to take the virtual machine down. Microsoft demonstrated this capability a few times with a Windows guest operating system, and to me, this feature stood out the most as it seemed to be something new and innovative and could have a lot of great use case potential.

Finally, Microsoft said that it was going to reduce the number of supported processors or cores from 64 to 16. Today as an example, that means it would support a server with a maximum of 16 processing cores which can be made up of eight dual-core or four quad-core processors. This to me is the least important feature drop today, although with multi-core technology changing quickly, it may become more important next year. I’m sure it will be used as a marketing battle cry when trying to compare products, however right now, its about as important to me personally as saying that your product will support a virtual machine with 128GB of memory. It sounds great, but what kind of x86 host server am I going to buy to consolidate virtual machines that are assigned 128GB of memory each? Not exactly a mass market need right now… but I agree, it does sound good.

News about delays always comes as a shock or a disappointment. Mike Neil, general manager of virtualization strategy at Microsoft, explained that it was necessary to scale back the scope of the virtualization platform, but assured everyone that it would be delivered on time.

“So we had some really tough decisions to make”, Neil said. “We adjusted the feature set of Windows Server virtualization so that we can deliver a compelling solution for core virtualization scenarios while holding true to desired timelines.” When talking about product development, Neil said that “the quality bar, the time you have, and the feature set are directly correlated. The mythical man-month – resources are not infinite and even if you could add more it does not help get more done faster.”

And thinking about it, as important as the live migration and hot-swap capabilities are, it is more important to get the core of the hypervisor product working as close to flawlessly as possible. Since everything gets built on top of this technology, it can’t be the weak link.

So with these three features pulled from the initial release of Viridian, how does that change the outlook of the product? Will it affect those people waiting to get into virtualization? Analyst firm IDC says that only 5% of hardware servers are virtualized. So what exactly are people waiting for?

Without the live migration and hot-swap capabilities, Microsoft’s Viridian will still be useful for the traditional, basic virtualization use case scenarios such as simple server consolidation, development and testing, and legacy application hosting, but probably won’t offer the solutions needed for the larger and more sophisticated organizations needing workload management, disaster recovery and failover mechanisms.

So while this news does come as a disappointment, there is still plenty of goodness coming in the initial release. Some of the key features of Viridian include hardware-based virtualization, a 64-bit hypervisor, delivery as a server core installation to offer better performance and secure virtualization, native support for clustering and geo-clustering with Longhorn, support for Volume Shadow Services (VSS) for backing up and replicating virtual machines, and new virtual switch capabilities that allow for Windows Network Load Balancing (NLB) across virtual machines on different servers.

Microsoft competitors will surely grab hold of this marketing baton and run with it. Hopefully, this delay doesn’t cause complacency in the virtualization ecosystem and slow down the innovation coming out of other virtualization platform vendors. And if it doesn’t, how much further back will that put Viridian on the parity scale?