Starting with DB2 12, the only supported DB2 failover mechanism for SAP ABAP instances is the native failover capability provided by the DB2 Connect CLI driver. This capability is referred to as 'CLI Failover' in contrast to the 'SAP Failover' mechanism that was previously used by SAP.
It is highly recommended that you start now to switch your existing SAP instances that still use SAP Failover to CLI Failover.
Reference information about SAPs database connectivity configuration can be found in the latest SAP Database Administration Guide (available from SAP on DB2 for z/OS Community)
The following presentation contains supplemental information and valuable hints and tips for implementing CLI Failover:
CLI_Failover_v12.pdf:
