O'Reilly logo

Professional Microsoft® SQL Server® 2008 Administration by Steven Wort, Ross LoForte, Wayne Snyder, Ketan Patel, Brian Knight

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

17.6. Database Mirroring and Other High-Availability Solutions

Database mirroring is another weapon in the arsenal of SQL Server high-availability solutions. SQL Server 2008 provides at least four high-availability solutions. Of course, each solution has some overlaps with the others, and each has some advantages and disadvantages:

  • Failover clustering: This is a typical solution for high availability with a two-node Windows failover cluster with one SQL Server instance. Clustering is discussed in more detail in Chapter 20.

  • Database mirroring: For this discussion, we consider the high-safety mode with a witness.

  • Log shipping: SQL Server 2008 has built-in log shipping. Log shipping is discussed in detail in Chapter 19.

  • Transactional replication: For comparison purposes, we'll consider a separate distribution server with a single subscriber server as a standby if the publisher fails.

Let's compare database mirroring with these other technologies.

17.6.1. Database Mirroring and Clustering

Obviously, the most distinct difference between database mirroring and a Window failover cluster solution is the level at which each provides redundancy. Database mirroring provides protection at the database level, as you have seen, whereas a cluster solution provides protection at the SQL Server instance level.

As discussed in the section "Mirroring Multiple Databases," if your application requires multiple database dependencies, clustering is probably a better solution. If you need to provide availability ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required