Most storage network events are based on health transitions. For example, a health transition occurs when the state of a device goes from online to offline. It is the transition from online to offline that generates an event, not the actual offline value. If the state alone were used to generate events, the same events would be generated repeatedly. Transitions cannot be used for monitoring log files, so log events can be repetitive. To minimize this problem, attach thresholds to entries in the log files.
The software includes an event maximums database that keeps track of the number of events generated about the same subject in a single eight-hour time frame. This database prevents the generation of repetitive events. For example, if the port of a switch toggles between offline and online every few minutes, the event maximums database ensures that this toggling is reported only once every eight hours instead of every five minutes.
Event generation usually follows this process:
Note: Aggregated events and events that require action by service personnel (known as actionable events) are also referred to as alarms. Some alarms are based on a single state change and others are a summary of events where the event determined to be the root cause is advanced to the head of the queue as an alarm. The supporting events are grouped under the alarm and are referred to as aggregated events.