tailieunhanh - Microsoft SQL Server 2008 R2 Unleashed- P9

Microsoft SQL Server 2008 R2 Unleashed- P9: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 | 34 CHAPTER 1 SQL Server 2008 Overview Running SQL Server 2008 inside a virtual operating environment requires at least one license per virtual operating environment. Within each virtual operating environment the license allows you to run one or more instances of SQL Server 2008. The license for a virtual operating environment can be a server CAL license or a processor-based license. If using a processor-based license you must purchase a processor license for each processor that the virtual machine accesses. The total number of physical and virtual processors used by the virtual operating system environments cannot exceed the number of software licenses assigned to that server. However if you are running Enterprise Edition and all physical processors in the machine have been licensed you may run an unlimited number of virtual operating environments on that same machine. Multiple Instances of SQL Server An option to virtualization is multi-instancing. With multi-instancing multiple copies of SQL Server can be run concurrently in a single instance of an OS. Multi-instancing for SQL Server 2008 can take place both in a virtual environment or in a physical environment. Although multi-instancing offers a relatively high degree of isolation between copies of SQL Server 2008 this isolation takes place at the application level instead of at the OS level . In SQL Server 2008 the Workgroup and Standard Editions now allow you to run any number of instances of the server software in one physical or virtual operating system environment on the licensed server. Previously only the Enterprise Edition of the server license allowed multi-instancing. Summary This chapter examined the various platforms that support SQL Server 2008 R2 and reviewed and compared the various editions of SQL Server 2008 that are available. Which platform and edition are appropriate to your needs depends on scalability availability performance licensing costs and limitations. The information provided in this