From the course: VMware vSphere: Administer and Manage Resources

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Understanding shares

Understanding shares

- [Voiceover] In this video I'll explain how shares can be used to control resource contention. Shares define the relative priority of virtual machines as they compete for resources. When you allocate CPU and memory to a virtual machine, you're not guaranteeing it any physical resources. CPU instructions are scheduled on a physical processor is needed. Memory is thin provisioned. So shares are used to control which virtual machine gets priority access to those shared resources. Shares are only enforced during times of contention. This is different from reservations and limits which are enforced at all times. This approach is beneficial because it means that even a low priorty virtual machine can have all the resources it needs as long as those resources on the ESXi host are not constrained. Let's take a look at an example on how shares work. Here we see an ESXi host with two gigabytes of available memory. And now we start to boot up virtual machines on this host. Notice the resource…

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