Why can't I see all of the historic alarms for a device in the USM Alarm History view?

Document ID : KB000014294
Last Modified Date : 14/02/2018
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Question:

Why can't I see all of the historic alarms for a device in the USM Alarm History view?

Answer:

The USM alarm history shows all alarms with a specific nimid.  Whenever an alarm is cleared or acknowledged, nas forgets about all alarms associated with that nimid from that point and into the past.  If a newer instance of the same alarm comes in, that alarm will get a new nimid and the USM alarm history will only show the alarms from the clear and forward.