Advanced Server is Heart of Microsoft Scale-Out Strategy

NEW ORLEANS -- Windows 2000 Advanced Server lies at the center of much of Microsoft Corp.’s planning for "scale-out," the company’s term for incrementally adding servers to reach greater performance levels.

Microsoft ( used the recent Windows Hardware Engineering Conference (WinHEC) to lay out some of the features it is planning for the next version of Windows 2000, code-named "Whistler." When Microsoft releases the refreshed code sometime around 2001, Advanced Server is in line to receive some Windows 2000 Datacenter Server exclusives, such as four-node clustering failover support and Winsock Direct Path. Twin 32-bit and 64-bit versions are planned for Microsoft’s middle-of-the-road server SKU with the Whistler release, as well.

"The [next release of] Windows 2000 Advanced Server will also get four-node clustering support," said Carl Stork, general manager for Microsoft’s Windows Hardware Strategy Group, at WinHEC late last month.

Windows 2000 Advanced Server currently supports two-node failover clusters for high availability. Microsoft will introduce the ability to cluster four servers with this summer’s release of Windows 2000 Datacenter Server.

Microsoft has been considering including four-node clustering in Advanced Server for some time. Company officials told II ENT II at the Windows 2000 launch in February that customers were pushing hard for four-node failover clustering capabilities in Advanced Server.

The issue took on extra significance at that time when Microsoft revealed its decision to sell and support Windows 2000 Datacenter Server only on machines with at least eight processors. The licensing decision locked out customers who had been interested in using four-node failover clustering on lower-end machines.

The additions bring Advanced Server nearly all of the technologies Microsoft refers to under the umbrella term of clustering. The four-node clustering is based on Microsoft Cluster Services -- Wolfpack -- clustering, which is a way to ensure application availability by grouping servers together so they can pick up the workload if one of the servers fails.

The version of Windows 2000 Advanced Server that was released in February supports two-node Wolfpack clusters, a capability that is supported in Windows NT Server 4.0, Enterprise Edition.

Advanced Server already supported network load balancing (NLB) for spreading Internet traffic across up to 32 servers.

The Winsock Direct Path is an interconnect technology for fast communication among servers working on similar problems that is also being introduced this summer in Datacenter Server. The Winsock Direct Path API lets servers in a system area network bypass the network stack to turbocharge communications.

The only missing piece is Component Load Balancing (CLB), and that part is expected to be delivered with AppCenter Server sometime this year. Microsoft officials lump Windows 2000 Advanced Server in regularly with AppCenter Server as the route to horizontal scalability. AppCenter Server is supposed to support CLB and provide management of NLB clusters. It is intended to help administrators manage large Web server farms.

Microsoft is currently basing its Windows 2000 Server Appliance Kit on Windows 2000 Advanced Server. OEMs use the kit to build preconfigured Web servers designed for users to unpack, put in a rack, and plug into the Web server farm.

One element of Advanced Server Microsoft is not yet talking about expanding is memory, although hardware vendors are already pushing Microsoft’s licensing limit for Advanced Server.

Microsoft’s use of Intel Corp.’s ( 36-bit Physical Address Extensions (PAE) means Advanced Server could theoretically handle 64 GB of RAM. Microsoft currently licenses Advanced Server to support 8 GB of RAM.

Recently IBM Corp. ( came out with four-processor servers, the Netfinity 7100 and 7600, that support up to 16 GB of RAM. Other vendors, including Hewlett-Packard Co. (, Dell Computer Corp. (, and NEC Computer Systems Division (, already offer four-processor machines that support the Advanced Server limit of 8 GB of RAM.

Jim Garden, an analyst with Technology Business Research Inc. (, says IBM has the right idea, even though its machines’ memory capacity overshoot the capabilities of the Windows operating systems they are designed to complement.

"Requirement for memory in these systems doubles every 18 months," Garden says. "In the future we expect that those memory limits on Windows 2000 will increase. If the capability is available in a number of machines, the operating system will be under duress to be extensible."

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