Memory – not such a simple matter
Memory differs from CPU as it is a form of storage. Unlike CPU, which executes instructions as they enter the CPU, memory keeps information for a much longer period of time. We are comparing nanoseconds to seconds (or longer, up to months, depending upon the uptime of your VM). Information is stored in memory in standard block sizes, typically 4 KB or 2 MB. Each block is called a page. At the lowest level, the memory pages are just a series of zeroes and ones.
Keeping this concept in mind is useful as you review the memory counters. Memory has a very different nature compared to CPU, and the storage nature of memory is the reason why memory monitoring is more challenging than CPU monitoring.
Before you proceed with this section, you need to be familiar with vSphere memory management. The whitepaper at https://www.vmware.com/resources/techresources/10206 provides a good explanation. It is based on vSphere 5.0, but is still relevant in vSphere 5.5....
