Sun Cluster Data Service for SAP Guide for Solaris OS

Planning the Sun Cluster HA for SAP Installation and Configuration

This section contains the information you need to plan your Sun Cluster HA for SAP installation and configuration.

Configuration Restrictions

Caution –

Your data service configuration might not be supported if you do not observe these restrictions.

Use the restrictions in this section to plan the installation and configuration of Sun Cluster HA for SAP. This section provides a list of software and hardware configuration restrictions that apply to Sun Cluster HA for SAP.

For restrictions that apply to all data services, see the release notes for your release of Sun Cluster.

Limit node names as outlined in the SAP installation guide – This limitation is an SAP software restriction.

Configuration Requirements

Caution –

Your data service configuration might not be supported if you do not adhere to these requirements.

Use the requirements in this section to plan the installation and configuration of Sun Cluster HA for SAP. These requirements apply to Sun Cluster HA for SAP only. You must meet these requirements before you proceed with your Sun Cluster HA for SAP installation and configuration.

For requirements that apply to all data services, see Chapter 1, Planning for Sun Cluster Data Services, in Sun Cluster Data Services Planning and Administration Guide for Solaris OS.

After you create all of the file systems for the database and for SAP software, create the mount points, and put the mount points in the /etc/vfstab file on all of the cluster nodes – See the SAP installation guides, Installation of the SAP R/3 on UNIX and R/3 Installation on UNIX-OS Dependencies, for details on how to set up the database and SAP file systems.
Create the required groups and users on all of the cluster nodes – See the SAP installation guides, Installation of the SAP R/3 on UNIX and R/3 Installation on UNIX-OS Dependencies, for details on how to create SAP groups and users.
Configure Sun Cluster HA for NFS on the cluster that hosts the central instance if you plan to install some external SAP application servers – See Sun Cluster Data Service for NFS Guide for Solaris OS for details on how to configure Sun Cluster HA for NFS.
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.
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.

Standard Data Service Configurations

Use the standard configurations in this section to plan the installation and configuration of Sun Cluster HA for SAP. Sun Cluster HA for SAP supports the standard configurations in this section. Sun Cluster HA for SAP might support additional configurations. However, you must contact your Enterprise Services representative for information on additional configurations.

Figure 1 Four-Node Cluster with Central Instance, Application Servers, and Database

Illustration: The graphic's title describes the graphic.

Figure 2 Two-Node Cluster with Central Instance, NFS, Database, and Non-HA External Application

Note –

The configuration in Figure 2 was a common configuration under previous Sun Cluster releases. To use the Sun Cluster software to the fullest extent, configure SAP as shown in Figure 1 or Figure 3.

Figure 3 Two-Node Cluster With Central Instance, Database, and Development Node

Configuration Considerations

Use the information in this section to plan the installation and configuration of Sun Cluster HA for SAP. The information in this section encourages you to think about the impact your decisions have on the installation and configuration of Sun Cluster HA for SAP.

Failover and Scalable Applications

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 consideration 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.

Scalable Applications

Ensure that the SAPSIDadm home directory resides on a cluster file system - This consideration enables you to maintain only one set of scripts for all application server instances that run on all nodes. However, if you have some application servers that need to be configured differently (for example, application servers with different profiles), install those application servers with different instance numbers, and then configure them in a separate resource group.
Install the application server's directory locally on each node instead of on a cluster file system - This consideration ensures that another application server does not overwrite the log/data/work/sec directory for the application server.
Use the same instance number when you create all application server instances on multiple nodes - This consideration ensures ease of maintenance and ease of administration because you will only need to use one set of commands to maintain all application servers on multiple nodes.
Place the application servers into multiple resource groups if you want to use the RGOffload resource type to shut down one or more application servers when a higher priority resource is failing over - This consideration provides flexibility and availability if you want to use the RGOffload resource type to offload one or more application servers for the database. The value you gain from this consideration supersedes the ease of use you gain from placing the application servers into one large group. See Freeing Node Resources by Offloading Noncritical Resource Groups in Sun Cluster Data Services Planning and Administration Guide for Solaris OS for more information on using the RGOffload resource type.
Create separate scalable application server instances for each SAP logon group.
Create an SAP lock file on the local instance directory - This consideration prevents a system administrator from manually starting an application instance that is already running.

Configuration Planning Questions

Use the questions in this section to plan the installation and configuration of Sun Cluster HA for SAP. Insert the answers to these questions into the data service worksheets in Appendix C, Data Service Configuration Worksheets and Examples, in Sun Cluster Data Services Planning and Administration Guide for Solaris OS. See Configuration Considerations for information that might apply to these questions.

What resource groups will you use for network addresses and application resources and the dependencies between them?
What is the logical hostname (for failover services) for clients that will access the data service?
Where will the system configuration files reside?

See Configuration Guidelines for Sun Cluster Data Services in Sun Cluster Data Services Planning and Administration Guide for Solaris OS for the advantages and disadvantages of placing the SAP binaries on the local file system as opposed to the cluster file system.

Packages and Support

Table 3 and Table 4 list the packages that Sun Cluster HA for SAP supports.

Table 3 Sun Cluster HA for SAP Packages From Sun Cluster 3.0 7/01


Resource Type	Description
`SUNW.sap_ci`	Added support for failover central instance.
`SUNW.sap_as`	Added support for failover application servers.

The *_v2 resource types are the latest version of the resource types (RT) for Sun Cluster HA for SAP. The *_v2 resource types are a superset of the original RTs. Whenever possible, use the latest RTs provided.

Table 4 Sun Cluster HA for SAP Package From Sun Cluster 3.0 12/01


Resource Type	Description
`SUNW.sap_ci`	Same as Sun Cluster 3.0 7/01. See Table 3.
`SUNW.sap_as`	Same as Sun Cluster 3.0 7/01. See Table 3.
`SUNW.sap_ci_v2`	Added the `Network_resources_used` resource property to the Resource Type Registration (RTR) file.
	Retained support for failover central instance.
`SUNW.sap_as_v2`	Added the `Network_resources_used` resource property to RTR file. Added support for scalable application servers.
	Retained support for failover application servers