Chapter 8: Planning, Implementing, and Maintaining a High-Availability Strategy

Introduction

High availability is a buzzword in today’s networking world, and for good reason. Ensuring that the network’s resources are available to users when they need them is an important part of the network administrator’s job. Downtime—whether caused by a disk failure, a performance slowdown, data loss due to an attack, or the loss of an entire server due to a natural disaster such as fire or flood—cuts into worker productivity and impacts the business’s bottom line or the organization’s ability to accomplish its goals.

In this chapter, we look at the concept of high availability and how it can be attained. We’ll provide an overview of performance bottlenecks and what cause them, and show you how to identify such common system bottlenecks as memory, processor, disk, and network components. We’ll walk you through the steps of using the System Monitor utility to track server performance and show you how to use Event Viewer and service logs to monitor server issues, as well.

Next, we show you how to plan a backup and recovery strategy. We’ll introduce you to the Windows Backup Utility and ensure that you understand the differences between full, incremental, and differential backups. We’ll also discuss the use of the Volume Shadow Copy feature as a backup option. You’ll learn how to decide what information should be backed up. We’ll also show you how to back up user data, System State data, the Dynamic Host Configuration Protocol (DHCP) database, Windows Internet Name Service (WINS) database, Domain Name System (DNS) database, cluster disk signatures, and partition layouts. We’ll walk you through the process of using the Windows Backup administrative tool, including the Backup and Restore Wizard feature and the Advanced Mode feature. We’ll also discuss the use of command-line tools. Then we’ll talk about how to select your backup media, and you’ll learn about scheduling backups and how to restore data from backup when necessary.

We’ll address how to plan for system recovery using the Automated System Recovery (ASR) feature. You’ll learn about system services, how to make an ASR backup, and how to do an ASR restore. We’ll explain how ASR works and discuss alternatives to ASR such as the Safe Mode and Last Known Good boot options. Finally, we’ll discuss the importance of planning for fault tolerance, including solutions aimed at providing fault tolerance for local network connectivity, Internet connectivity, data on disk, and mission-critical servers.