Disaster Recovery and Data Networking

All modern data centers require some form of data backup or replication to protect the data from natural or man-made disasters and provide business continuity. Companies rely on their information systems to run daily operations. If a system becomes unavailable, company operations may be impaired or stopped completely. If critical data remains inaccessible for an extended period, the company may never recover and be forced to go out of business. It is necessary to provide a reliable infrastructure for IT operations in order to minimize any chance of disruption. In this chapter, we define the requirements for Tier 1 through Tier 4 data centers. We discuss the ACID-BASE (atomicity, consistency, isolation, durability-basically available, soft state, eventual consistency) taxonomies for data consistency, giving examples from companies such as Yahoo!, Amazon, Google, and IBM. The chapter includes a detailed discussion of the different options for IBM Geographically Dispersed Parallel Sysplex (GDPS), enterprise-class high-end business continuity, and disaster recovery solution, including the Sysplex Timer protocol, InterSystem Channel (ISC), Parallel Sysplex InfiniBand (PSIFB), and more.