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

Building an Extended Distance Cluster Using MC/ServiceGuard
Chapter 2 49
2 Building an Extended Distance
Cluster Using MC/ServiceGuard
Simple MC/ServiceGuard clusters are usually configured in a single data
center, often in a single room, to provide protection against failures in
CPUs, interface cards, and software. Extended MC/ServiceGuard
clusters are specialized cluster configurations, which allow a single
cluster to extend across two or three separate data centers for increased
disaster tolerance. Depending on the type of links employed, distances of
up to 100 km between data centers can be achieved.
This chapter discusses several types of extended distance cluster that
use basic MC/ServiceGuard technology with MirrorDisk/UX and
FibreChannel. Both two-data center and three data center architectures
are illustrated. The chapter discusses the following:
• Types of Data Link for Storage and Networking
• Two Data Center Architecture
• Two Data Centers and Third Location Architectures
• Rules for Separate Network and Data Links
• Guidelines on DWDM Links for Network and Data
NOTE Metropolitan and continental clusters, which include specialized data
replication techniques and which require the purchase of separate
software, are described in Chapters 3 through 7.