IP Storage Networking
Chapter 6: Business Continuity for mission critical applications
This book excerpt is from Chapter 6 of IP Storage Networking by Gary Orenstein, ISBN 0-321-15960-8, copyright 2003. All rights reserved. This chapter, titled "Business Continuity for mission critical applications," is posted with permission from Addison-Wesley Professional.
Business continuance encompasses several areas of an organization. Some of the factors taken into account when planning for business continuance include risk assessment, location specifics, personnel deployment, network infrastructure, operational procedures, and application/data availability. This chapter's main focus will be in the areas related to applications and data availability.
Varying degrees, or levels, of availability can be achieved for applications based on the tools and technologies employed. The levels of availability range from simple disk failure resilience to quick business resumption after a complete data center outage. The tools and technologies range from disk mirroring to sophisticated automated wide area fail-over clusters. Of course, cost and complexity increase in proportion to increasing levels of availability.
To better understand the levels of availability and the associated array of tools and technologies, we start with the simple case of an application residing on a single server with data on non-redundant direct attached storage, and walk through the process of progressively building higher levels of availability for this application.
This chapter includes sections on the following topics:
- Assessing Business Continuity Objectives
- Recovery Time Objective (RTO)
- Recovery Point Objective (RPO)
- Factors Affecting the Choice of Solution
- Availability Within the Data Center
- Backup and Restore
- Disk Redundancy-RAID
- Quick Recovery File Systems
- High Availability and Clustering Availability Across Geographies-Disaster Tolerance and Recovery
- Off-Site Media Vaulting and Recovery
- Remote Mirroring and Fail-Over
- Data Replication
- Modes of Replication
- Methods of Replication
- Secondary Site-Recovery and Other Considerations
- Corporate Systems
- Internal Websites
- External Websites
- Enterprise Applications-ERP,CRM,Supply Chain, etc.
- Making Use of Storage Redundancy Layers
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