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Data Retention

By default, Alarm Analysis retains all data. The Alarm Analysis application is designed so that it can comfortably execute monthly reports irrespective of how much Alarm & Event history is stored. However, at some point you may wish to expire data to free storage capacity.

The article below provides guidance on configuring a data retention policy.

How Alarm Analysis Stores Data

Alarm & Event data is stored in montly indices. Depending on how Alarm & Import has been configured, there may be two types of monthly index.

Alarm Analysis Message
The cleaned and transformed Alarm & Event record. Optimized for big data operations.

Source Event Cache
A raw Alarm & Event arrives on the import flow. Minimal parsing is undertaken - only enough to allow the record to be stored along with meta information such as “where it came from” and “time of arrival”.

The Source Event Cache could be removed once the raw record has been transformed to an Alarm Analysis record. However, this may prevent future retaining the source object facilitates re-import, which can be useful - particularly when first definining and configuring transformation rules. If the Source Event Cache it may be difficult (or impossible¹⁾ to apply transformation rules to historic data if the Source Event Cache has been removed.

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Alarm Analysis supports many different types of import flow. A source data provider may remain available for future retrieval (e.g. a datafile or database repostitory). However, in other cases the event data source may be ephemeral (e.g. OPC), and it is the responsibility of Alarm Analysis' to collect as well as process.