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Fundamentals of vSphere Performance Management

March 31st, 2010 3 comments

Performance monitoring is a critical aspect of vSphere administration. This article introduces you the basic concepts and terminologies in vSphere performance management, for example, performance counters, performance metrics, real time vs historical statistics, etc. Much of the content is based on my book VMware VI and vSphere SDK by Prentice Hall.

Once you understand these basics, the related tools and APIs should be relatively easy. If you are already familiar with vSphere Client performance monitoring or esxtop, they help as well.

Performance Counter

A performance counter is a unit of information that can be collected about a managed entity. PerfCounterInfo data object, shown in Figure 1, represents a performance counter. The property key is an integer that uniquely identifies a performance counter, like a primary key of a table in SQL database, and nothing more. There is no guarantee for a performance counter to have a fixed number. In fact, the same performance counter can have different values in ESX and VirtualCenter. Even for the same type of server, the number could change from version to version. Do not use it outside the context of the server you connect to.

Figure 1 PerfCounterInfo data object

The performance counter can be represented by the following dotted string notation: