Maintaining a resource-optimal vSphere infrastructure is a critical day-to-day operation and should be performed with a strict focus on delivering adequate resources to the virtual machines (VMs) at any given time.

The resources of your vSphere infrastructure are limited, even though vSphere provides many overcommitment techniques so that you can assign more resources than you physically have, but you should try to avoid contention scenarios at all costs because such contention can significantly affect your applications' and workloads' performance.

One of the fundamental techniques that you can use to provide the best possible performance to your VMs is resources, limits, and shares, which you can use to fine-tune resource allocation to different vSphere objects, such as VMs, vApps, and resource pools.

Using vMotion, you can freely move your workloads within a vSphere cluster, allowing you to utilize the ESXi hosts evenly.

For more complex environments, you can also utilize Distributed Resource Scheduler (DRS), a cluster feature that is not only responsible for maintaining your cluster balance automatically but also provides advanced functions that allow you to specify how the VMs should be run concerning different affinity and anti-affinity rules.

Resource pools, on the other hand, can provide you with a pool of computing and memory resources that VMs inside the resource pool can consume without taking more than you have defined, and by using vApps you can even extend this functionality to complex application management, where you treat multiple VMs as a single logical application.

This chapter covers the following topics:

• Virtual machine resource management
• Virtual machine migration
• DRS
• Resource pools and vApps
• Network and storage resources