Managing Serviceguard Extension for SAP, December 2007

Understanding Serviceguard Extension for SAP
The Replicated Enqueue
Chapter 1 35
Dedicated Failover Host
More complicated clusters that consolidate a couple of SAP applications
often have a dedicated failover server. While each SAP application has its
own set of primary nodes, there is no need to also provide a failover node
for each of these servers. Instead there is one commonly shared
secondary node that is in principle capable to replace any single failed
primary node. Often, some or all of the primary nodes are partitions of a
large server.
Figure 1-6 Dedicated Failover Host
Figure 1-6 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.
SGeSAP Cluster
Dedicated Failover Server
with Replicated Enqueue
shared disks
+ Dialog
Instances
failover paths from all primary
partitions to the dedicated backup server
node 1
node 2
node n
jdbscsC11
dbascsC12
dbscsCnn
ers00C11
ers10C12
ersnnCnn
. . .