Specifications

Introduction 15
failing server comes back online and takes over its applications, then this process
is known as
fail back .
The second phase of Microsoft Cluster Server will implement failover with more
than two servers and the third phase will incorporate workload balancing and
cluster management solutions for NT servers.
IBM has certified three fundamental hardware configurations for Microsoft Cluster
Server. They are listed on the Microsoft Hardware Compatibility List (HCL). Only
Microsoft-certified hardware configurations will be supported.
You can find the Microsoft HCL on the World Wide Web at
http://www.microsoft.com/hwtest/hcl.
The disk controller and the shared subsystems are the main criteria for a MSCS
certification.
The certified configurations are:
• The external hardware-implemented RAID enclosure system Symbios Logic
MetaStor DS-20E combined with a differential SCSI controller
• The external SCSI storage expansion enclosures IBM 3518, IBM 3519 and
IBM EXP10 combined with the IBM ServRAID II Ultra SCSI Adapter
• The external storage subsystem IBM 7133 for Serial Storage Architecture
(SSA) combined with the IBM SSA Raid Cluster Adapter
Note: The SSA Solutions are only supported in Netfinity 7000 and PC Server
704 for SAP R/3.
In addition, IBM developed an MSCS tool called the IBM Cluster Systems
Manager (ICSM). It brings you enhanced management control of clustered
environments and delivers integrated systems management functions for the
management tools IBM Netfinity Manager, Intel LANDesk and Microsoft Systems
Management Server (SMS). With ICSM you will get a tool to simplify your
administrator tasks throughout GUI-based dynamic and intuitive use of wizards,
configurable alert generation and single-console view to the cluster topology.
The SAP AG modified the R/3 kernel software for optimized MSCS support and
added some programs and special Dynamic Link Libraries (DLL) to espouse the
particular capabilities of the MSCS, so that it will be the clustering solution of
choice for R/3 implementations. The SAP AG will deliver R/3 NT with MSCS as a
standard solution and provide a switchover kit for clustering as a change to the
SAP R/3 kernel 3.1H. But this version is a first customer shipment (FCS), which
means the SAP AG will deliver it only to hardware partners and selected
customers. This version is for test use only. The later versions of SAP R/3 3.1I or
4.0B with the switchover kit will then support production environments.
The SAP AG supports for clustering all Microsoft-certified and MSCS-enabled
databases. Currently only Oracle offers with Oracle fail-save such a solution for
MSCS. Other products such as MS SQL Server, Informix and DB2 will follow.