The integrated event history is one of the most fundamental parts of Tembria Server Monitor. When an event monitor runs it generates one event history record for each network device that it checked. The event history record tells you whether or not the check was successful and the event text tells you what was checked and what the result was.
By default, Tembria Server Monitor keeps a maximum of 50,000 event history records. When the limit is exceeded the newest event history record pushes out the oldest one. You can change this number by going to the “Event History Settings” in the “Settings and Preferences” section of the tree.
Event History Settings
So what’s a good value? On average hardware, say a modern desktop PC with 2G of RAM and a single core processor, we recommend keeping the value to 200,000 records or less. On a higher end system like a quad-core server class machine you can bring it up to perhaps 750,000 records or more. The exact reasonable value will depend on the machine in question and on your monitoring configuration too.
That said, we’ve noticed though that many users aren’t aware of the various options we offer to manage the creation of event history records.
Let’s say you’re using our Ping event monitor to watch 100 machines every 30 seconds. You’re going to be generating a tremendous number of event history records with the default settings. The important question is: Are you ever going to want to look at all of these records? It’s unlikely that you could, even if you wanted to. You’re likely only interested in the ones that failed either due to a machine being unreachable or a response time threshold being exceeded.
In this case our recommendation is to set your event monitor to only write to the event history on failure or, if you prefer, on state change. With the “on failure only” option you’ll only get event history records for failed checks. With “state change only” you’ll get one record when a device check fails and one when it comes back online. And here’s the part that’s not obvious: You’re still collecting graph data for all the other checks.
Event Monitor Notification Styles
So you get the best of both worlds. Your event history will be uncluttered and easy to browse because it only contains records for important events, plus you get the long term trending data in the graphs.
Posted by Don
