Microsoft SQL Server 2008 R2 Unleashed- P69:SQL Server 2005 provided a number of significant new features and enhancements over what was available in SQL Server 2000. This is not too surprising considering there was a five-year gap between these major SQL Server 2008 is not as much of a quantum leap forward from SQL Server 2005 | 624 CHAPTER 20 Database Mirroring advise that you use something that is repeatable such as SQL scripts and you can easily generate SQL scripts by using the new wizard. It s not fun to have to re-create or manage a database mirroring configuration in the middle of the night. Having this whole process in a script reduces almost all errors. Getting Ready to Mirror a Database Before you start setting up and configuring a database mirroring environment it is always best to run through a simple checklist of basic requirements 1. Verify that all server instances are at the same service pack level. In addition the SQL Server edition you have must support database mirroring. 2. Verify that you have as much or more disk space available on the mirror server as on the principal server. You also need the same room for growth on both. 3. Verify that you have connectivity to each server from the others. You can most easily do this by trying to register each SQL Server instance in SSMS. If you can register the server the server can be used for database mirroring. Do this for the principal mirror and witness servers. 4. Verify that the principal server database that is to be mirrored is using the full database recovery model. Right-click on the database you intend to mirror choose Tasks and then Mirroring. This brings you to the database mirroring properties dialog where you can configure mirroring. If you try to start configuring database mirroring and the database recovery model is not full for the principal database you get a nasty message to that effect see Figure . Because database mirroring is transaction log based it makes sense to be using the full database recovery model all transactions are written to the transaction log and are not truncated as with other database recovery models. FIGURE Trying to mirror a database that is not using the full database recovery model. Before you go any further you must establish the endpoints for each of the servers that will be
