I've found that the Snapshot Alarm size Alarm is reporting higher snapshot size data than what is reported in the Top N Active VM snapshot size report.
If I set the snapshot size alarm to absolute and set a value of like 30GB for warning and 40GB for error. The alarm will trigger and state in the data the size is 43GB. Ok, so far works as expected.
In the report, it says the snapshot size is 35.70GB and if I look at the actual delta files, this is correct. Across the board the alarm is stating a good bit higher snapshot size, sometimes off by as much as 50GB (too high)
How specifically does the alarm determine the size of the snapshot? ... I'm wondering if it's not the way we have things configured as we do have a third party system that creates the VMs and if I knew how it determined the size I might be able to figure it out.