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Many applications can be adapted to take advantage of MSCS’failover feature. These applications must be able to use TCP/IP and use remote storage for its data. (Applications that keep a significant state information in memory are not the best applications for clustering because any data not stored on disk is lost at failover.) Applications that can be failed over can support MSCS API or not. Those applications that support the MSCS API are MSCS-aware. MSCS-aware applications can be registered with the Cluster Service to receive status and notification information and use the MSCS API to administer clusters.

Although MSCS protects the availability of data, not the data itself in a cluster, the Windows NT Server has built-in features including mirroring and redundant array of inexpensive disks (RAID Level 5, stripping with parity). The following table lists common points of failure in a Windows NT Server environment and suggests protection methods:

Point of Failure

MSCS

Other

 

 

 

Network hub

Redundant networks

Consider stocking replacement

 

 

network components

 

 

 

Power utility

 

Uninterruptable power supply (UPS)

 

 

provides power for 5 to 20 minutes for

 

 

a proper shutdown

 

 

 

Disk

 

RAID array

 

 

 

Server hardware (CPU or memory)

Failover

DIGITAL Servers 5000 and 7000

 

 

series provide redundant power and

 

 

cooling

 

 

 

Storage

Failover

StorageWorks RA3000, 450, 7000

 

 

offer redundant power, cooling,

 

 

cache, controllers, cache batteries

 

 

Consider stocking replacement disks,

 

 

controllers, SCSI components

 

 

 

Server software (operating system

Failover

 

or applications)

 

 

 

 

 

WAN links (routers and dedicated

 

Redundant links over the WAN,

lines)

 

providing secondary access to remote

 

 

connections

 

 

 

Dial-up connection

 

Multiple modems

 

 

 

Computer

 

Multiple clients for the same level of

 

 

access

 

 

 

Any client that can connect to Windows NT Server through TCP/IP will work with MSCS. This includes Microsoft MS-DOS®, Microsoft Windows® 3.x, Windows 95, Windows NT, Apple® Macintosh®, and UNIX®. MSCS does not require any special software on the client for transparent recovery of services that connect to clients through standard IP protocols.

For more information on MSCS, see http://www.microsoft.com/ntserver/support/clusterfaq.asp#basics.

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DIGITAL Server Cluster Kits for Windows NT Configuration Guide

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Compaq DIGITAL Server Cluster Kits for Windows NT manual Point of Failure, Other