Designing Disaster Tolerant High Availability Clusters, 10th Edition, March 2003 (B7660-90013)

Building a Continental Cluster
Understanding Continental Cluster Concepts
Chapter 5180
Two packages are running on the cluster in Los Angeles, and their data
is replicated to the cluster in New York. Physical data replication is
carried out using ESCON (Enterprise Storage Connect) links between
the disk array hardware in New York and Los Angeles via an
ESCON/WAN converter at each end. The New York cluster is running a
monitor that checks the status of the Los Angeles cluster. In this
example, the Los Angeles cluster runs just like any ServiceGuard
cluster, with applications configured in packages that may fail from node
to node as necessary. The New York cluster is configured with a recovery
version of the packages that are running on the Los Angeles cluster.
These packages do not run under normal circumstances, but are set to
start up when they are needed. In addition, either cluster may run other
packages that are not involved in ContinentalClusters operation.
Mutual Recovery Configuration
Bi-directional failover is now supported in what is called a mutual
recovery configuration. This lets you define recovery groups for primary
packages running in both component clusters in the ContinentalClusters
configuration. Figure 5-2 shows a mutual recovery configuration.
Figure 5-2 Sample Mutual Recovery Configuration
NYnode1 NYnode2
LAnode1 LAnode2
monitor
custpkg
Cluster
Los Angeles
N
ew
Y
or
k
WAN
Highly Available
Network
Data Replication Links
Disk
Disk
Array
Array
monitor
ESCON/WAN converter
salespkg
Cluster