Managing HP Serviceguard Extension for SAP for Linux, December 2013

Figure 7 Dedicated failover server
SGeSAP Cluster
Dedicated Failover Server with
Replicated Enqueue
Failover paths from all
primary partitions to the
dedicated backup server
jdbscsC11
Node 1
dbascsC12
Node 2
ers00C11
ers10C12
ersnnCnn
Dialog Instances
dbscsCnn
Node 3
Shared Disks
Figure 7 (page 18) shows an example configuration. The dedicated failover host can serve many
purposes during normal operation. With the introduction of Replicated Enqueue Servers, it is a
good practice to consolidate a number of Replicated Enqueues on the dedicated failover host.
These replication units can be halted at any time without disrupting ongoing transactions for the
systems they belong to. They are sacrificed in emergency conditions when a failing database and
or Central Service Instance need the spare resources.
2.8 Example 6: Scale-out HANA System Replication and Dual-purpose
SAP HANA System Replication is a database replication feature used to deploy highly available
SAP HANA databases. SAP HANA System Replication requires an active primary database system
and a standby secondary database system.
If the secondary database system is located near primary system, it serves as a failover solution
for planned downtime or unplanned downtime (server failures, software failures, storage corruption
and so on). If the secondary system is located remotely, it provides disaster recovery solution. Using
System Replication, the database content of the production system is replicated from primary to
secondary SAP HANA database system. The primary and secondary system are either paired in
18 SAP cluster concepts