Microsoft® SQL Server® 2012 Bible

685

CHAPTER

27

Database Mirroring

IN THIS CHAPTER

Understanding the Database Mirroring Overview

Confi guring Database Mirroring

Monitoring Database Mirroring

Pausing or Removing Database Mirroring

Using Role Switching

Experiencing High Availability/AlwaysOn

Confi guring AlwaysOn Availability Groups

Monitoring AlwaysOn Availability Groups

A

chieving high database availability is one of the most important goals for critical business

applications. Database mirroring is a software solution offered by Microsoft SQL Server 2012

to achieve high database availability. Database mirroring enables you to maintain a copy of

your production database that could potentially be completely synchronized on a separate server

for failover if a failed production server or database occurs. Like log shipping, database mirroring

provides high availability at the database level, but unlike log shipping, you can confi gure data-

base mirroring to provide no data loss and automatic failover.

What’s New in SQL Server Database Mirroring?

One of the most exciting new enhancements in SQL Server 2012 is the AlwaysOn Availability Groups feature,

which is the next evolution of the existing mirroring technology. With AlwaysOn Availability Groups, SQL Server

2012 enables you to have multiple, readable secondary databases. AlwaysOn Availability Groups also allows

you to group databases together so that in the event of failure they will fail over together.

Another important thing to note is that as of the release of SQL Server 2012, the Database Mirroring fea-

ture is being listed as a deprecated feature. What this means is Database Mirroring will be supported in the

next release of SQL Server but will be removed in a later version. Microsoft recommends you use AlwaysOn

Availability Groups to replace your current mirroring confi gurations. If your edition of SQL Server does not

support AlwaysOn Availability Groups it is suggested you that you use log shipping instead.

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