Failover and Scalable Applications

• Use an SAP software version that is qualified with Sun Cluster 3.0.

• Use an SAP software version with automatic enqueue reconnect mechanism capability - Sun Cluster HA for SAP relies on this capability. SAP 4.0 software with patch information and later releases should have automatic enqueue reconnect mechanism capability.

• Retrieve the latest patch for the sapstart executable - This patch enables Sun Cluster HA for SAP users to configure a lock file. For details on the benefits of this patch in your cluster environment, see "Setting Up a Lock File".

• Read all of the related SAP online service-system notes for the SAP software release and database that you are installing on your Sun Cluster configuration - Identify any known installation problems and fixes.

• Consult SAP software documentation for memory and swap recommendations - SAP software uses a large amount of memory and swap space.

• Generously estimate the total possible load on nodes that might host the central instance, the database instance, and the application server, if you have an internal application server - This guideline is especially important if you configure the cluster to ensure that the central instance, database instance, and application server will all exist on one node if failover occurs.

• Install application servers on either the same cluster that hosts the central instance or on a separate cluster - If you install and configure any application server outside of the cluster environment, Sun Cluster HA for SAP does not perform fault monitoring and does not automatically restart or fail over those application servers. You must manually start and shut down application servers that you install and configure outside of the cluster environment.

• Limit node names as outlined in the SAP installation guide - This limitation is an SAP software requirement.