SQL Server license with multi-core CPU technology, confusing concepts?
How many SQL Server licenses you need to fix the number of CPUs on the server?
The answer it depends on the number! Well having hyper-threading (i.e. multiple threads execute on a single physical CPU appearing as 2 logical CPUs) and dual-core technology (i.e. a single CPU socket that has more than 1 core appearing as multiple logical CPUs) is a common aspect on the default server configuration. SO when you shop for a server the processor & chip vendors are keeping it a default configuration of with more than 2 cores.
So there was a big question within forums and user-group meetings that say if we have multi-core processors (4-core) what would be the licensing cost or how many licenses we should deploy?
So within the SQL Server 2005 release this confusion has been releaved somewhat where the purposes of both licensing and CPU edition support, SQL Server considers the number of physical sockets/CPUs, regardless of the number of cores on the processor, cool isn't it. Taking this into real-world example if you are planning to license a SQL Server 2005 Standard Edition box that will support upto 4 CPUs which means it will only support 4 physical CPU sockets, regardless of the number of cores in each CPU. So as we talked above having dual-core on these 4 physical processors each then the logical deployment would have 16 logical CPUs to make use of. This will avoid any additionaly spending of license on 16 processors (logically) as you only have to pay for the 4 physical CPUs, not all 16 cores.
Not just take a word, but rather it would be advantageous in discussing for these new CPU options, research these options with your hardware vendor of choice to see what opportunities are available with their latest and greatest servers. Don't forget the golden rule that if the application is CPU bound then better to fine-tune the associated queires and not the server configuration tuning such as number of CPUs or memory, make sure to research on the multi-core opportunities to meet your CPU needs. So for all the needs and information on SQL Server licensing also consider the reference the SQL Server Multicore Licensing Policy article.
