Sooner than analysts were expecting, Microsoft announced on Thursday it is adding add TCP/IP clustering and load balancing to its Windows NT Server Enterprise Edition.
The new NT feature, called Windows NT Load Balancing Service (WLBS), is based on the critically acclaimed Convoy Cluster product from Valence Research. Microsoft acquired the company in August 1998. The technology already powers most Microsoft Web sites, as well as Centraal's Realnames service.
WLBS allows up to 32 Windows NT servers to be clustered together. The software will evenly distribute TCP/IP traffic over the clustered servers, automatically redistributing the load if one server fails.
WLBS can be used for TCP/IP based network services such as Internet/Intranet servers, proxy servers and media servers, said Karan Khanna, product manager for Windows NT Server at Microsoft.
The new NT service is separate from Windows NT Cluster Server (NTCS), formerly codenamed Wolfpack. NTCS offers two node failover - but no load balancing - for back end servers such as database servers. WLBS is positioned for the front end. Both clustering services complement each other, said Khanna.
A third type of clustering will further complement - or complicate - Microsoft's portfolio by the time Windows 2000 ships, later this year.
This third cluster type will form the mid tier of a three tier Internet architecture, containing the business logic, explained Khanna. It will allow load balancing of COM+ (Component Object Model Plus) objects over an eight node cluster.
Also in the Windows 2000 time frame, NTCS will move up to four node support, said Khanna.
The stand alone version of Valence Convoy Cluster will no longer be available, said Khanna. This means that any company wishing to benefit from load balancing will have to move to Windows NT 4.0 Enterprise Edition.
Windows NT Server 4.0 Enterprise Edition has a list price of $3,500, including 25 client access licenses. This compares to a $1,600 sticker for the standard NT Server edition with 25 client access licenses. All current users of Enterprise Edition are eligible for a free uprade to WLBS.
Microsoft's clustering plans have often changed and often been delayed. Originally Microsoft said it would offer multiple node support and load balancing in Wolfpack Phase II, once expected to ship in 1998. "Customers were asking us to deliver clustering at all three tiers," explained Khanna, "And so the definition of clustering is broadening."
"It was great to see how [Microsoft] managed to turn [WLBS] around and get it out there so quickly," said Dan Dolan, an industry analyst with Dataquest, "But this doesn't let them off the hook for NTCS," he added.
"There's a lot of pressure on Microsoft right now, because Intel and some of the other [operating system] vendors are ready for the enterprise," concluded Dolan, "If Microsoft wants to be a player in the enterprise, they'd better get going."
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