When estimating your hardware requirements, the first step is to determine the event ingestion rate (for Transaction Analytics) or the amount of data being indexed (for Log Analytics). This helps you to determine the number of analytics license units you will need.

Once you determine your license units requirements, it is important to consider other factors that affect the hardware capacity, such as the processing load of queries run against the Events Service and the actual type of hardware used. A physical server is likely to perform better than a virtual machine. You should also take into account seasonal or daily spikes in activity in your monitored environment in your considerations.

An event is the basic unit of data in the events service. In terms of application performance management, a Transaction Analytics event corresponds to a call received at a tier. A business transaction instance that crosses three tiers, therefore, would result in three events being generated. In application performance management metrics, the number of business transaction instances is reflected by the number of calls metric for the overall application. In End User Monitoring, each page view equates to an event, as does each Ajax request, network request, or crash report.