Serviceguard Extension for SAP Version B.04.02 and B.04.51 Release Notes, December 2007

Serviceguard Extension for SAP Versions B.04.02 and B.04.51 Release Notes
What’s In this Version
Chapter 18
Automated Replicated Enqueue Support for SAP ERS Components
SGeSAP now provides a failover for ERS (Enqueue Replication Service) instances, as well as
support for Enqueue Replication technologies for both ABAP and JAVA based SAP
applications. It is possible to create add-in configurations with two replications for a single
SAP system in parallel.
NOTE When using a failover for ERS, although the old naming convention with
REP/AREP instance names are still supported, they should no longer be used.
SGeSAP supports up to 16 nodes in a replication cluster. The automation feature implements
a follow-and-push behavior for the packages that include Enqueue and its replication.
Therefore, Enqueue and its replication server are never started on the same node initially.
Enqueue will not invalidate the replication accidentally by starting on a non-replication node
while replication is active elsewhere. It is possible to move the package with the replication
server to any free node in a multi-node cluster without a requirement to reconfigure the
Enqueue package failover policy.
During failover of Enqueue, its replication will be located dynamically and the Enqueue
restarts on the currently active replication node. Enqueue synchronizes with the local
replication server. As a next step, the package with the replication service shuts down
automatically and restarts on a healthy node, if available. In case of a failover in a multi-node
environment this implements a self-healing capability for the replication function. Enqueue
will failover to just any node from the list of statically configured hosts if no replication
package is running.
NOTE Automated Replicated Enqueue is providing similar functionality to SAP
releases including Netweaver as HP Somersault provides for SAP 4.x kernels.