VMware vSphere hosts are designed to utilize memory efficiently like other resources. The resource management policies are implemented in the vSphere host to allocate memory to the virtual machines it is hosting. This allocation is based on the allocated memory setting of a virtual machine and the current system load. The vSphere host reveals different memory statistics that can be viewed using esxtop. Before we start looking into memory statistics, let's look at a brief introduction of how a vSphere host manages its memory.
Figure 2.6
Before we take a look at vSphere host memory metrics, I will walk you through memory management in a vSphere host system briefly. The memory management concept in a vSphere host will help you to understand the metrics displayed by esxtop. A vSphere host reclaims memory to provision memory overcommitment.