tailieunhanh - Microsoft SQL Server 2008 R2 Unleashed- P111

Microsoft SQL Server 2008 R2 Unleashed- P111: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 | 1044 CHAPTER 32 Database Snapshots the primary transactional database without any data loss impact whatsoever. This is a very powerful reporting and availability configuration. What s New with Database Snapshots With SQL Server 2005 everything about database snapshots was new because this was a completely new feature for SQL Server. With SQL Server 2008 there is little new to this feature other than under-the-cover improvements to the copy-on-write mechanisms and three more years of production implementations under their belt. One hundred percent of the SQL code you have set up for creating and managing snapshots will work perfectly with SQL Server 2008. No upgrade pain here. Database snapshots have solved many companies reporting data safeguarding and performance issues and directly contributed to higher availability across the board. Be aware though there are plenty of restrictions with doing database snapshots. In fact these restrictions may prohibit you from using snapshots at all. We talk about these restrictions and when you can safely do database snapshots in a bit. NOTE The examples in this chapter are based on the SQL Server 2005 version of the AdventureWorks database rather than the newer AdventureWorks2008 or AdventureWorks2008R2 sample databases used for many of the examples in the other chapters in this book. The reason for this is because of the examples presented that create a snapshot from a Database Mirror. Database Mirroring cannot be implemented on a database that is also configured for FILESTREAM storage. The 2008 and 2008R2 versions of the AdventureWorks database make use of FILESTREAM storage. Fortunately the 2005 version of the AdventureWorks database can be installed using the same installer that installs the AdventureWorks2008 or AdventureWorks2008R2 database. If you didn t install AdventureWorks when you installed either of these sample databases simply relaunch the installer and choose to install the AdventureWorks OLTP database. For more