Events Alerts Incidents and Problems

ITIL v3 introduced Event & Alert management which goal is to set appropriate alert levels such that events can be acted upon before they become incidents, while at the same time avoiding alerts from insignificant activities.

Before going deeper, let's revise the vocabulary:

An event is a detectable or discernible occurrence that has significance for the management of the IT infrastructure.

An alert is triggered by specific events and needs immediate attention.

An incident is an event which is not part of the standard operation of a service and which causes or may cause disruption to or a reduction in the quality of services and customer productivity.

A problem is a cause of one or more existing or potential incidents.

So when the hard drive of a server reach 50% usage, an event will record the information for trend analysis. When it reaches 80% usage, an alert might be triggered. Once at 100% usage, chances are you have an incident and potentially a problem to be investigated.