SNA Server in a Cluster Server Environment

Windows NT Server, Enterprise Edition includes Microsoft Cluster Server (MSCS) for increased server availability. SNA Server is not cluster aware, therefore it cannot exploit the full set of clustering capabilities when deployed as a cluster server resource, but it can be installed on cluster hardware.

SNA Server exhibits the following limitations:

• SNA Host Connections do not failover when a connection is lost.
• SNA Server Services do not failover when installed once on a cluster drive configured in a cluster group as a resource.
• SNA Server does not provide utilities to ease the installation of SNA Server on MSCS to set up the required registry parameters to failover.

Due to some of the limitations of not being cluster aware, SNA Server does not include the capability of detecting failing connections and services in order to transition them to a surviving node in the cluster. For these reasons, Microsoft SNA Server versions 2.11, 2.11 SP1, 2.11 SP2, 3.0, 3.0 SP1, 3.0 SP2, 3.0 SP3, 4.0, and 4.0 SP1 services are not supported when deployed in a cluster group as a resource. However, SNA Server can be installed on Windows NT Server Enterprise Edition and can exploit the native hotbackup and load-balancing features as explained in Knowledge Base article 128244  (http://support.microsoft.com/kb/128244/EN-US/ ) that are available when installed on both nodes of a cluster.

COM Transaction Integrator for CICS and IMS, OLE DB Provider for AS/400 and VSAM, and the ODBC Driver for DB2 can be deployed as a cluster resource using the Windows NT client for SNA Server. The Readme.doc file that comes with SNA Server can be used as a reference for configuring the Windows NT client for SNA Server and its SNA-Aware applications.