I’ve just published a new document or guide that is subtitled as “Understanding, enabling, and configuring Windows Server 2008 R2 Hyper-V Dynamic Memory for virtualised workloads”.
This whitepaper will walk you through:
- The mechanics of Windows Server 2008 R2 SP1 Hyper-V Dynamic Memory
- The scenarios that you’ll employ it in
- The pre-requisites for Dynamic Memory
- Configuring Dynamic Memory
- Some of the application workload scenarios
“We normally don’t like it when a service pack includes new features. New features mean changes that need to be tested, possible compatibility issues, and more headaches in between the usual operating system deployment cycles. Windows Server 2008 R2 Service Pack 1 came with a number of new features but we did not complain; in fact, we virtualisation engineers had a mini celebration. This is because those new features were mostly targeted at server and desktop/session virtualisation, and aimed to give us a better return on hardware investment.
Dynamic Memory was one of those new features. Put very simply, this VM memory allocation feature allows us to get more virtual machines on to a Hyper-V host without sacrificing performance.
You can use Dynamic Memory in a few scenarios. The one that gets the most publicity is virtual desktop infrastructure (VDI) where economic PCs are replaced by expensive virtual machines running in the data centre. It’s critical to get as many of them on a host as possible to reduce the cost of ownership. Server virtualisation is the scenario that we techies are most concerned with. We’ve typically found that we tend to run out of memory before we get near to the processor or storage I/O limits of our hardware. And the final scenario is where we use Hyper-V to build an Infrastructure-as-a-Service cloud, where elasticity and greater virtual machine density are required.
The approach that Microsoft took with this new memory optimisation technique ensures that concepts such as over commitment are not possible; that’s because over commitment potentially does cause performance issues. Dynamic Memory does require that you understand how it works, how to troubleshoot it, and how applications may be affected, before you log into your hosts and start enabling it. It will require some planning.
The aim of this document is to teach you how Dynamic Memory works, show you how to configure it, how to monitor it, and how to use it in various application scenarios”.
The document continues …
Big shout out to the Hyper-V PMs and my fellow MVPs for the many conversations over the past year that allowed us to learn a lot.