Hyper-V is finally here – almost. With the recent delivery of Release Candidate 1, Microsoft is shifting from major engineering operations mode to cross-the-i's-and-dot-the-t's mode. The majority of the Hyper-V bits, including an ever-expanding list of supported guest operating systems, are now in place, and Microsoft customers can start migrating their test VMs into preproduction and production roles with a fair degree of confidence.

The Bottom Line Microsoft Windows Server 2008 Hyper-V RC1 Microsoft, microsoft.com Good  7.7 criteria score weight Manageability 7 25% Scalability 8 25% Usability 8 25% Setup 8 15% Value 7 10% Platforms: Hyper-V requires Windows Server 2008 64-bit; MSCVMM runs on Windows Server 2003 and Windows Server 2008. Guests officially supported: 32-bit and 64-bit versions of Windows Server 2008, Windows Server 2003, and Suse Linux Enterprise Server 10; 32-bit versions of Windows Vista and Windows XP Professional. Cost: Hyper-V is a standard feature of Windows Server 2008 Standard, Enterprise, and Datacenter Edition. Microsoft Hyper-V Server, a stand-alone edition of Hyper-V for a single physical server, will be available for an estimated MSRP of $28. Bottom Line: Microsoft's attempt at toppling VMware VI3 is chock-full of classic embrace-and-extend goodness, including support in System Center Virtual Machine Manager 2008 (tested in beta) for managing VI3 assets. The Hyper-V hypervisor technology is sound and should scale well enough to challenge VMware's ESX Server. However, Microsoft still lags in the area of high availability, though the functionality in Virtual Machine Manager should be good enough to deliver wins in less demanding virtualization environments. About our Reviews and Scoring Methodology

Unfortunately, the same can't be said for the company's uber-management solution for Hyper-V hosts and their VMs – namely, Microsoft System Center Virtual Machine Manager 2008. Only recently entering public beta, MSCVMM (a mouthful of an acronym) shows promise but is hindered by the inherent limitations of Hyper-V, especially by its inability to perform live VM migrations.

[ One of Hyper-V's advertised strengths -- the host partition's ability to work with generic Windows device drivers -- is also its greatest weakness: See "Hyper-V's Achilles' heel."
Read Tom Yager's review of Windows Server 2008.
Read Paul Venezia's review of VMware Infrastructure 3 with ESX Server 3.5 and VirtualCenter 2.5 ]

First, the good news: MSCVMM introduces a new, more streamlined UI for managing Microsoft's myriad virtualization environments, which now include Hyper-V as well as the legacy Virtual Server product line. The MSCVMM console provides quick access to common tasks while allowing you to filter the view in useful ways. Major functions, like controlling VMs and managing the asynchronous Jobs engine, are broken out into logical subgroups with Vista-esque Action panes appearing on the right side of the window according to the task being performed. Each subgrouping provides copious filtering options allowing you to focus, for example, on recently added hosts or VMs in a specific state. It's a simple mechanism but one that can make a world of difference when managing a large virtualization farm.

Library science
Also helpful is MSCVMM's library for storing VM images. The cornerstone of Microsoft's transition from workgroup VM also-ran to datacenter player, the MSCVMM library makes it easy to distribute and track VMs across a growing Microsoft virtualization infrastructure. Simply select the desired VM from the MSCVMM administrator console and assign it to the desired target host server. The MSCVMM library servers and agents take care of the rest, including copying the VM image (plus any snapshots) to the corresponding physical server and bringing it online. Combined with the new Quick Migration feature – which is basically a rapid snapshot-and-move operation, using the network as transport – MSCVMM's maturing library model should make it easier to scale Hyper-V to levels previously reserved for the VMware Infrastructure 3 product suite.

The bad news: Unfortunately, manageability is one of the only areas where Microsoft is close to catching VMware. The company has no answer for features like VMotion, which allows for seamless movement of VMs across servers with zero downtime. Microsoft had planned such a feature for Hyper-V but had to scrap it in order to meet its planned ship date of "six months after Windows Server 2008 launches." And while Quick Migration (which leverages Microsoft Cluster Server technology) makes shifting VMs between hosts less problematic, it still requires that the virtual machine be taken offline during the transfer – not an option for environments where high availability is a must.

Further, Hyper-V's official support for Linux as a guest OS is limited to Suse Linux Enterprise Server 10; all other Linux variants are treated as second-class citizens. Others may work, but only Suse gains installation support and extensions to improve integration (such as mouse/keyboard integration between guests and the host OS) and performance/scalability on Hyper-V. By contrast, VMware's ESX Server supports dozens of Linux variants directly by providing guest OS integration components (namely VMware Tools) to improve their performance and behavior on the ESX platform. But of course, Hyper-V's target market is consolidation of Windows servers, and nobody should be surprised that Microsoft is giving short shrift to its biggest competitive threat.