'Viridian' Beta Delayed. Is Longhorn Next?

Published: April 18, 2007

by Alex Woodie

Work on "Viridian," the codename for the hypervisor virtualization technology that Microsoft is developing for Windows Server "Longhorn," is going slower than expected. As a result, Microsoft says the first public beta of Viridian, which had been scheduled for release by the end of June, will now be delayed to the second half of the year. Despite the importance that Viridian poses to Longhorn, Microsoft says the delay won't have any impact on the current schedule to ship Longhorn by the end of the year, but questions remain.

Product delays are nothing new in the software business, and they affect nearly all consumers of IT. One rarely hears about products that ship earlier than scheduled, assuming that the vendor has even released a development timeline or a roadmap. In fact, that's the primary reason many IT vendors don't publicize details about their product release schedule, because they know they're probably not going to honor it, and that diminishes their credibility. As time moves forward, as the bits pile up and the complexity of compatibility with past and current products grows, the problem only seems to be getting worse, and the product delays continue.

Microsoft, as the most important software provider for the majority of the world's computer users, has no choice but to publicize a timeline, but it does so only for some of its products, and often using vague six- or 12-month release windows that provide plenty of room for error. The software giant prefers to develop products at its own pace, and to finalize code when managers feel the product is good and ready, as opposed to accountability to an externally defined schedule.

But because thousands of companies have paid Microsoft millions of dollars with the expectation that they'll receive product updates and new products as part of their multi-year maintenance agreements, Microsoft, like other enterprise IT providers, must strive to find a happy medium, and--most importantly--try to ship products in a timely manner. Even the best of intentions can't stop delays from happening, of course, but the company must show that it's making an effort.

And that is the rock and the hard spot that Microsoft currently finds itself between: The commitment to deliver Longhorn with all the promised good stuff (like the Viridian hypervisor, but also features like Server Core, Network Access Protection, IIS 7.0, and better cluster failover) before its largest customers' Software Assurance contracts expire, and the reality that developing new operating systems and virtualization technology is tedious, time-consuming, and difficult.

On Thursday, Mike Neil, general manager of Microsoft's virtualization strategy, announced the availability delay of the first public beta of Viridian from the first half of the year to the second half. He also announced that the release of Virtual Server 2005 R2 Service Pack 1 (SP1) will ship in the second quarter, not in the first quarter as previously scheduled. Neil made the announcement on the Windows Server Division WebLog.

Neil says the delays around Viridian--which Microsoft is developing with help from open source virtualization software provider XenSource--have to do with performance and scalability. Microsoft's internal goals for the performance and scalability of Viridian are not being met, Neil says. "We still have some work to do to have the beta meet the 'scale up' bar we have set," he says. "Also, we're tuning Windows Server virtualization to run demanding enterprise IT workloads, even I/O intensive workloads, so performance is very important and we still have some work to do here."

Microsoft has set some fairly high scalability and performance goals for Viridian. "We're designing Windows Server virtualization to scale up to 64 processors, which I'm proud to say is something no other vendor's product supports," Neil says in his blog. "We are also providing a much more dynamic VM [virtual machine] environment with hot-add of processors, memory, disk, and networking as well a greater scalability with more SMP [symmetric multi-processor] support and memory."

This appears to be the first time Microsoft has committed to completely virtualizing big 64-way X64 machines. That would give Viridian an edge over its competitors in the X64 virtualization world, including VMware, XenSource, and Virtual Iron. But it still wouldn't trump the virtualization capabilities that are available in the RISC world of Unix, Linux, and i5/OS servers.

Other Viridian details previously released include the addition of virtual I/O capabilities, an expansion of the limit of the amount of memory each VM can handle from 4 GB to 32 GB per VM, and the capability to support up to eight processors per VM (macro-partitioning). Still unknown is how many VMs it will support per chip (its micro-partitioning limit, which is the real virtualization target), if there will be a cap on the number of VMs supported per SMP machine, disk limits, and which file systems and operating systems will be supported.

Neil also attempted to quell any question that the Viridian setback will spill over into Longhorn. "Up front, it's important to know that Windows Server 'Longhorn' remains on schedule for beta 3. [Beta 3] will be this half and RTM [released to manufacturing] in the second half." Despite the delay in ending the private beta of Viridian and moving onto the public test, Microsoft is sticking to its plan to deliver Viridian within 180 days of the release of Longhorn.

There is no doubt that Viridian is critical to Longhorn. Perhaps more than any other new capability, the new hypervisor comes closest to being the "killer feature" that companies will pay to get, even if it won't be available for six months after Longhorn ships. Of course, we thought similar things about how important Windows File System (WinFS), the replacement to the NT File System, would be to Windows Vista and Longhorn Server. Microsoft ripped WinFS out of Longhorn a long, long time ago and set it on a separate development path, but not much is heard about WinFS anymore.(It went to beta 1 20 months ago, where it died; current plans call for WinFS features to appear in "Katmai," the next version of SQL Server, where it won't have nearly the impact it would have had if it were included as part of the operating system.

Could the same thing that happened to WinFS be happening to Viridian? Probably not. The market for virtualization software and the impact a good virtualization product will have is much more defined than the benefits WinFS would have brought.

Just the same, Microsoft faces some tough choices about what it can do with Viridian. It could delay the product, which would seem to be the most likely scenario (and, ironically, one that Microsoft bristled at just weeks ago following an errant, but eerily prescient, report out of the MMS 2007 conference that Viridian had been delayed). Secondly, it could limit its scalability and performance ambitions for Viridian, thereby delivering a hypervisor more or less on time, with commitments to improve it down the line. Or it could delay Longhorn to give its development team more time to work out the kinks in Viridian, which seems unlikely.

Alternatively, Microsoft could crack the whip on its developers and demand they burn the midnight oil, Windows XP SP2-style, to deliver Viridian on time, with all the features and capabilities Microsoft has internally committed to. Or, Microsoft could deliver the software ahead of schedule, with more capability than anyone ever expected, pleasing both its customers and the industry at large. But I wouldn't hold my breath on that.

RELATED STORIES

Microsoft Taps Xen to Help Build Longhorn's Hypervisor

Microsoft Unveils "Viridian" Hypervisor, Extends Virtualization Roadmap

Microsoft Working on New Virtualization Technologies for Longhorn

WinFS No Longer Part of Windows Roadmap

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