Mapping and Visualizing your Data Center

5 August 2019

Ben Simpson


Correctly licensing and managing your data center can be a minefield of vendor small print. Misunderstanding how virtualization technologies can change the licensing required for key strategic vendors can lead to large amounts of unknown and unexpected risk. The key to ensuring you are not caught out by licensing terms that affect virtualization is to understand and clearly see the virtualization.

Technologies such as Dynamic Resource Scheduling (DRS) allow VMs to move between the physical hosts supporting a virtual environment. Benefits such as capacity management ensuring reliability and uptime can actually cause issues with licensing.

Technologies guiding your data centre visualization

A great example of this is within Microsoft licensing. A universal term of Microsoft licensing states that a license cannot be moved more than once every 90 days which would mean in a dynamic virtual environment every time a VM has resided on a physical host within 90 days would require a license (e.g. a single VM with SQL Server deployed that has been on five separate hosts over a 90 day period will mean that five licenses of SQL are required).

To get around this restriction, Microsoft offers different methods of licensing with the main feature to aid utilization of virtual technology being Software Assurance coverage (Microsoft’s maintenance, essentially). Products such as SQL Server and Office Productivity servers gain additional rights which overwrite the 90 day re-assignment rule when covered with Software Assurance.

To add further complexity within Microsoft licensing and specifically SQL Server, you can license either per virtual machine, or you can license a host (Enterprise Edition only) with Software Assurance. This provides an unlimited number of VMs on that host with SQL VMs. Alternatively you can license without Software Assurance, and instead license the number of cores as the number of VMs that can have SQL deployed.

Now consider the myriad of licensing options available in what are now common virtual data center deployments. There are multiple ways the server could be licensed within a virtual environment: Firstly what was deployed, with regards to software, hosts, mobility, and licensing applied. Secondly, what the rules are for the product deployed – licensing must cover the deployment. Finally how the deployment can be optimized to get the most out of any existing licensing while ensuring the required level of redundancy exists within the data center (you didn’t invest in advanced virtual technology to turn off all the features!).

A SAM tool to map your data centre

Managing and applying licenses to these complex scenarios requires information from your hypervisor technology for both the structure of your data center as well as VM movement. Inventory data for the VMs which reside within the infrastructure for processors, cores, and software deployed. A good SAM tool will bring all of this information together to show you where a VM sits and what’s installed within which virtual cluster. The more advanced part, which is very much tool dependant, is representing the licensing required based on how you want to license it.

A market leading SAM tool should apply licensing at host level if server affinity rules are used (the ability to restrict which hosts a VM resides on). It should create phantom VMs to show the license requirement/demand caused by the movement of a VM, which is bound to the 90 day reassignment rule; in fact it should show where a VM has been within 90 days to ensure Server Affinity rules are implemented correctly. It should be able to apply a license with active maintenance (Software Assurance in this SQL example) and compensate for this removing and phantom instances created to truly manage advanced data center scenarios.

SAM tools that just provide virtual machine inventory and data center structure are now not fit for purpose. There is so much variety available in licensing to cover the data center, these legacy tools will never provide a true compliance position to ensure customers are aware of their full licensing risk. The ability to correctly align deployments to accurate licensing based on mobility, host licensing, additional maintenance use rights, and license metrics is the only way to have full confidence a SAM tool is accurate.

It is only after achieving this true view of risk that an organization can look to optimize their position and start using the differing licensing metrics and terms to efficiently license their estate, start saving, and feel confident in procurement decisions and risk management.

Ben supports organizations to understand their software risk, working with them to ensure the most efficient procurement solutions to achieve their strategy. With over a decade of experience, he works closely with his customers to provide software cost optimization advice.

Ben Simpson

Further reading