Microsoft May Bring Four-Node Clustering to Advanced Server

Microsoft Corp.’s recent moves to solidify the high-end positioning of its forthcoming Windows 2000 Datacenter Server leave many customers without an upgrade path to native four-node failover clustering. But that could change.

"A lot of customers and OEMs wanted to use four-node technology on lower-end systems," says Michel Gambier, product manager for Windows 2000 enterprise marketing at Microsoft ( "We’re looking at bringing down four-node technology into Windows 2000 Advanced Server."

Microsoft’s failover clustering, formally called Microsoft Cluster Service (MSCS) and commonly known by its code-name Wolfpack, is slated for two versions of Windows 2000 -- Advanced Server which was released Feb. 17 and Datacenter Server scheduled for release in June.

Advanced Server supports two-node failover clustering, enhancing only the functionality and setup of clusters over Windows NT 4.0 Server, Enterprise Edition.

Datacenter Server will support failover clusters of up to four different machines. That upgrade to the core functionality of Wolfpack clustering makes it possible to bring down the cost of high-availability configurations. In one example, instead of having a standby server waiting for the failure of one active server, an organization could assign that standby server to three active servers.

Many customers were looking forward to the release of Datacenter Server to upgrade some of their existing two-node clusters of one- to four-processor machines to four-node clustering.

Other anticipated features of Datacenter Server include support for up to 64 GB of memory, up to 32 processors, a process control manager, support for system area networks, and a special Hardware Compatibility List for enhanced reliability.

With the general launch of Windows 2000 last month, Microsoft further defined its promise of a special Hardware Compatibility List with the introduction of the Windows Datacenter Program. Under the new program, OEMs must pass compatibility testing for complete systems that will run Datacenter Server. Hardware compatibility testing for Windows NT and for other versions of Windows 2000 only involves checking individual components for compatibility.

The more sharply defined program was applauded by analysts who believe it shows Microsoft is serious about challenging Unix in the lower end of the data center.

But as part of the program, Microsoft clarified that the Windows Datacenter Program would only concern itself with eight-processor capable servers and larger systems. And the only way to acquire a licensed copy of Datacenter Server is through a qualified server vendor or OEM in the

Datacenter Program selling the OS with a complete system. Translation: Under current plans, there is no way to acquire four-node failover clustering technology for less-than-eight-processor-capable machines.

"Room for growth is really key in high-end systems," Gambier says of the customer requirements driving Microsoft’s decision to qualify only eight-processor-capable machines.

Although Microsoft had not finalized its plans for adding four-node clustering to Advanced Server as of mid-March, customers currently have third-party options.

Users can get to greater-than-two-node failover clusters through the use of third-party software, just as they could with Windows NT 4.0. Last April, IBM Corp. ( announced its Cornhusker software, which allows up to eight-node failover clustering, and it achieves this using the Wolfpack API.

Analysts urged Microsoft to hurry its native four-node clustering capabilities into Advanced Server. "Clearly there’s a need even by rank-and-file users to have higher availability through much more robust clustering," says Laura DiDio, an analyst with Giga Information Group (

Microsoft has responded to customer pressure in the past with Windows 2000 licensing issues. The company originally planned to limit SMP support in Windows 2000 Server to two processors and in Advanced Server to four processors for new licenses. Widespread complaints led to the existing limits of four-processor support in Windows 2000 Server and eight-processor support in Advanced Server. – Scott Bekker

Related URLs:

W2K Advanced Server Clustering: Better than NT 4, But at a Price (

W2K Cluster Upgrades: Apps Will Work But Why Hurry? (

About the Author

Scott Bekker is editor in chief of Redmond Channel Partner magazine.

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