tailieunhanh - Microsoft SQL Server 2008 R2 Unleashed- P59

Microsoft SQL Server 2008 R2 Unleashed- P59: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 | 524 CHAPTER 18 SQL Server High Availability What s New in High Availability In general a couple of Microsoft SQL Server 2008 configuration options offer a very strong database engine foundation that can be highly available 7 days a week 365 days a year . Microsoft s sights are set on being able to achieve five-nines reliability with almost everything it builds. An internal breakthrough introduced with SQL Server 2005 called copy-on-write technology has enabled Microsoft to greatly enhance several of its database high availability options. Here are a few of the most significant enhancements and new features that have direct or indirect effects on increasing high availability for a SQL Server 2008-based implementation Increased number of nodes in a SQL cluster You can create a SQL cluster of up to 64 nodes on Windows Server Data Center 2008. Enhancements to do unattended cluster setup Instead of having to use wizards to set up SQL clustering you can use the Unattended Cluster Setup mode. This is very useful for fast re-creation or remote creation of SQL clustering configurations. All SQL Server 2008 services as cluster managed resources All SQL Server 2008 services are now cluster aware. SQL Server 2008 database mirroring Database mirroring creates an automatic failover capability to a hot standby server. Chapter 20 Database Mirroring covers this topic in detail. SQL Server 2008 peer-to-peer replication This option of data replication uses a publisher-to-publisher model hence peer-to-peer . SQL Server 2008 automatic corruption recovery from mirror This enhancement in database mirroring recognizes and corrects corrupt pages during mirroring. SQL Server 2008 mirroring transaction record compression This feature allows for compression of the transaction log records used in database mirroring to increase the speed of transmission to the mirror. SQL Server 2008 fast recovery Administrators can reconnect to a recovering database after the transaction log has been rolled .