Setting up ABAP SCS, Java SCS, and ERS instances

This information describes how to configure the ABAP and Java™ variants of SAP Central Services (SCS). Each SCS variant may contain an enqueue replication server (ERS) instance. Therefore, this topic also describes the configuration of the corresponding ERS instances. To install the mentioned components, follow the instructions that are provided in the contained subtopics. Start with implementing the prerequisites documented in this parent topic.

1. Set up a highly available network.
   You must use lowercase (virtual) host names. Refer to the sample TCPIP.PROFILE provided in Network setup. As the GLOBALTCPIPDATA statement in this sample is GLOBALTCPIPDATA(/etc/resolv.conf), the mapping in this case would have to be done in the file /etc/resolv.conf.

   Note: If you want to defer the network setup step, then you must, as a minimum, define the virtual host names that are used in the SAP installation to refer to already active IP addresses. Keep in mind that such a procedure means that you must reassign the correct IP addresses of the correct subnets afterward. This in turn means that you must verify the functionality of the complete SAP system again.
2. Define and activate the dynamic and static VIPAs defined within your z/OS TCP profile (see z/OS VIPA usage for the high availability solution for SAP). Make sure that the VIPAs can be reached under their corresponding virtual host names. The dynamic VIPAs and their corresponding virtual host names are necessary in order to move applications (here NFS server, ASCS/SCS instances, and ERS instances) from one cluster node to another within a cluster. Each application and instance requires its own virtual host name so that it can be moved independently from another.

   As a minimum you need:

   • One dynamic VIPA for the highly available z/OS NFS server
   • One dynamic VIPA for ASCS instance and another one for its ERS instance
   • One dynamic VIPA for SCS instance and another one for its ERS instance
   • n static VIPAs, where n is the number of LPARs, which run a Db2® data sharing member for your SAP system. You may alternatively use n own dynamic VIPAs, one for each Db2 data sharing member. Then, you must ensure that the dynamic VIPA is started together with the corresponding Db2 DS member on the correct LPAR. However, this alternative is not supported by the standard *Db2 add-on policy so that in this case you need to manually adapt the policy.

   It is suggested that you define your virtual host names that use the following naming conventions with lowercase virtual host names as required:

   Used for	Static or dynamic VIPA	Sample virtual hostname	IP address
   Highly Available z/OS NFS Server	dynamic VIPA	sapnfsv
   ASCS instance	dynamic VIPA	ha1ascsv
   ABAP ERS instance	dynamic VIPA	ha1aersv
   SCS instance	dynamic VIPA	ha1scsv
   Java ERS instance	dynamic VIPA	ha1jersv
   (LPAR of) Data-sharing member n	Static VIPA	coh<n>vipa (COH<N> is the LPAR name)

   If you decide to run the SAP Web Dispatcher or the SAProuter, or both, under z/OS UNIX you need another dynamic VIPA for each.

   You can activate a dynamic VIPA via a command from z/OS UNIX. For example, if 10.101.5.194 is the IP address of ha1ascsv, an authorized user can activate it using the following command:

   moddvipa -p tcpip -c 10.101.5.194 

3. Set up a high availability NFS server as described in Preparing a high availability SAP solution.
4. Define group and user IDs and add <sid>adm to the z/OS UNIX USERIDALIASTABLE, according to the Security Guide for SAP on IBM® Db2 for z/OS and the Planning Guide for SAP on IBM Db2 for z/OS.
5. Download the latest version of SAP Software Provisioning Manager for z/OS from the SAP Software Download Center.
6. Set up WLM definitions according to the Planning Guide for SAP on IBM Db2 for z/OS.
7. Set up the file systems as described in Preparing a high availability SAP solution.