High availability for SAP on IBM i can be accomplished by using and configuring at least two hosts and a switchable Independent Auxiliary Storage Pool (IASP) that is shared between the two hosts. This scenario enables you to switch from one host to the other, either in a planned way for maintenance activities (“switchover”) or in an unplanned way in case of an error (“failover”). To avoid host name changes after a switchover or failover, SAP suggests to configure a virtual host name and IP address that is moving from the primary host to the backup host in case of a switchover or failover. IBM is offering PowerHA software to automate the switchover and failover for all components that are involved.
For a comprehensive planning and setup guide for IASP and IBM PowerHA, you can refer to SAP Note 1635602 and its attachments. If you don’t install a new SAP system but want to move an existing SAP system from the System ASP (*SYSBASE) into an IASP, you can use SAP Note 568820. This SAP Note has two setup guides for releases before and after SAP NetWeaver 7.0. The toolset is shipped through the SAP kernel component ILE (database independent) and has been reworked recently to provide a more user-friendly interface, better error checking and handling, as well as improved performance. If you are planning any activity using the toolset, we highly recommend that you the ILE patch levels that are listed in SAP Note 568820.