vCenter 5.5 provides 28 counters for RAM to track the various features of ESXi memory management. Compared with physical servers, where you normally just monitor the memory utilization and swapping, these are a lot counters. I have shown all the counters in the next screenshot. With 28 counters per VM, a vSphere environment with 1,000 VMs will have 28,000 counters just for VM RAM! It is certainly too many to be monitored as part of overall management. I will share, in the later part of this chapter, the three key counters you need to track to manage performance and capacity.

VM – RAM counters

At the ESXi level, vCenter provides 33 counters. As you can expect, some of the counters at the ESXi level are essentially the sum of associated counters of all VMs running in the host, plus VMkernel's own memory counters (since it also consumes memory). This aggregation is useful as VMs do move around within the cluster. Since there are a lot of counters, let's compare...