HP Serviceguard Extended Distance Cluster for Linux A.01.00 Deployment Guide, Second Edition, May 2008

Disaster Tolerance and Recovery in a Serviceguard Cluster
Understanding Types of Disaster Tolerant Clusters
Chapter 128
Figure 1-6 Continental Cluster
Continentalclusters provides the flexibility to work with any data
replication mechanism. It provides pre-integrated solutions that use HP
StorageWorks Continuous Access XP, HP StorageWorks Continuous
Access EVA, or EMC Symmetrix Remote Data Facility for data
replication.
The points to consider when configuring a continental cluster over a
WAN are:
• Inter-cluster connections are TCP/IP based.
• The physical connection is one or more leased lines managed by a
common carrier. Common carriers cannot guarantee the same
reliability that a dedicated physical cable can. The distance can
introduce a time lag for data replication, which creates an issue with
data currency. This could increase the cost by requiring higher speed
WAN connections to improve data replication performance and
reduce latency.
• Operational issues, such as working with different personnel trained
on different processes, and conducting failover rehearsals, are made
more difficult the further apart the nodes are in the cluster.
node 1b node 2b
pkg A_R pkg B_R
node 1a
node 2a
pkg A
pkg B
Data Center A
Los Angeles Cluster:
Data Center B
New York Cluster:
WAN
Data Replication
and/or Mirroring
High Availability Network