Considerations for Deploying Physical or Virtual Machines – Server 2012
May 22, 2013 Leave a comment
Virtualization enables you to be more efficient in the way that you allocate resources to servers.
Instead of allocating separate hardware to a server that minimally uses resources, you can virtualize that server and enable those minimally used hardware resources to be shared with other virtual machines.
When deciding whether to deploy a server physically or virtually, you must determine how that server uses hardware resources. Consider these points:
•Servers that constantly put hardware under resource pressure are poor candidates for virtualization. This is because virtual machines share resources. A single virtual machine that uses a disproportionate amount of hypervisor resources can have an adverse effect on other virtual machines hosted on the same hypervisor.
•Servers that put minimal pressure on hardware resources are good candidates for virtualization. These servers are unlikely to monopolize the host resources, ensuring that each virtual machine hosted on the hypervisor can access enough hardware resources to perform adequately.
For example, a particular database server that heavily uses disk and network resources would be more appropriately deployed on a physical computer. If it were deployed as a virtual machine, other virtual machines on the same hypervisor would have to compete for access to those heavily used disk and network resources. Alternatively, allocating a physical platform to a server that requires minimal hardware resources, such as a server running Certificate Services, means that powerful hardware is underused.
Following our other considerations when determining whether to deploy a server virtually or physically:
•High Availability. After you have built a highly available virtual machine cluster, any virtual machine deployed to that cluster also becomes highly available. This is simpler than setting up separate failover clusters for physical servers that host the same role.
•Scalability. Moving a virtual machine with its associated applications and data to a new host platform is much simpler than migrating a physically deployed server, its applications, and its data to a new host platform. If you must quickly scale up capacity, you also can migrate a virtual machine to a cloud provider; that is far more difficult to do with a physically deployed server.