Understanding sql server licensing is very important for planning upgrades or building new servers. This blog does not cover every licensing scenario but should help understanding the general basics of SQL 2012/14 license options.
There are two types of license models available 1. Core based license 2. Server + cal license.
Microsoft implemented core based license from sql 2012 and is the only option to buy enterprise edition. While other editions such as standard is available in both the above options. In sql 2008, it used to be socket based license.
Another key point is the core form factor chart. Microsoft has assigned form factor value based on the number of cores in the physical processor and this should be multiplied with total number of cores while determining the licenses you need.It should be rounded to the nearest higher integer,if the value is in decimal.The core form factor chart can be downloaded here.
Another important requirement is minimum of 4 core licenses per processor. That means, even if the physical processor has less than 4 cores, you still need to buy 4 licenses. This is something that’s important to remember while doing in place upgrades as most new processors have 4 cores at minimum.
The formula to calculate licenses:
No of physical processors * No of cores per processor * Core form factor
Scenario: I have a new server that has 4 quad core processors. If I want to install sql 2012 enterprise edition as a stand alone instance on the physical box, i need to buy 16(4*4*1)licenses.
Consider the same scenario but with dual cores, we would still need 16 licenses because the minimum per core license is 4. This means we are spending more money for less benefit. That’s why planning is important.
Also, all the available physical processors have to be licensed. In the above example,you cannot license just two of the processors(8 cores),all 4(16 cores) have to be licensed.
However, there are couple of workarounds for this
1. Disable the two processors in bios settings
2. Install VM and assign just two processors for it.
I will cover other types of licensing models in another blog post.