Search code examples
mongodbperformancemongodb-atlas

What do the timeline annotation lines actually represent in the mongodb atlas Metrics?

I'm currently investigating a mongo incident in our Atlas cluster. I am trying to figure out why it decided to upgrade for a period of time. I know that something happened around the memory so I've been looking at the System Memory metric in Atlas. In the charts there are lines added that are described as DISPLAY TIMELINE ANNOTATIONS.

enter image description here

enter image description here

I can see one of these lines around the time of my "incident". The problem is nothing seems to explain what these lines represent? Looking on the mongo Atlas docs it simply states:

Directs Ops Manager to display or hide chart annotations. Chart annotations consist of colored vertical lines that indicate server events, such as a server restart or a transition in member state.

So what exactly is a "server event"? How do I find these and what do the various colours mean?

Solution

  • I raised a support ticket with mongo to get this information. It seems it is shown on the chart but it's a bit hidden because you need to press the i in the top left, which only appears when you hover your mouse cursor over the chart:

    enter image description here

    enter image description here

    • Red - Server restart
    • Orange - server is now primary
    • Brown server is now secondary