Chapter 11. High availability with database mirroring
In this chapter, we’ll cover
- High-availability options
- Transaction log shipping
- Database mirroring
- Automatic and manual failover
- Setup and administration tasks
When the term high availability is used in the context of a SQL Server deployment, features such as database mirroring and failover clustering are almost always the focus of attention. While their contribution to a highly available SQL Server environment is beyond question, they should be seen as a single, albeit important, component of a much broader solution.
Every topic in this book can be viewed in the context of high availability. Security breaches, corrupt backups, and poor maintenance practices can all contribute to unexpected outages and missed availability targets. In many ways, high availability is as much a state of mind as it is a feature or installation option.
This chapter begins with a broad overview of a number of high-availability options and compares their relative strengths and weaknesses. We then cover transaction log shipping, which in many ways can be considered an extension of the previous chapter. Our focus then shifts to database mirroring and how it can be used in contributing to a highly available SQL Server environment.