I was just messing with alert tuning and was looking for a way to plot the trend lines to help adjust the math appropriately.
I first looked to the metric explorer and found I could add a threshold line (which seems relatively new). It generates a default line, which looks like it might be a linear mean calculated on the fly over whatever time interval is in the window at the time; however, once that line is set it is a static threshold on the graph.
Of course, I can see the trend under Alert History and Current Trend State, but that only seems to show the the last 30 minutes or so with a straight trend line. I was looking for something where I could track the trend over time, then tune the alert.
After that I went to the Custom App Page and added a Trend Chart there. It seems like it has been an age since I did anything with pages - ever since dashboards more or less supplanted them. On the one hand, it was nice to get back to the basics. On the other hand, I am a bit surprised I can’t chart trends on a dashboard for easy reference against triggered alerts. Am I missing something?