Strange red horizontal line in graph, source unknown?

1

I have been using Grafana for about a year, mostly to display “past 12 hours” of voltage/current data on my off-grid solar power system. Recently I notice a static horizontal red line on my graphs, independant of the scale/timeframe, it’s not grabbable and does not show up in the hover-over value display. What could it be? I’ve searched all the settings, metrics, axis etc. screens and can’t find whats causing it.

funny-grafana-line-cropped
funny-grafana-line-cropped1299×484 44 KB

Can anyone tell me what that is and how to remove it? I’m sure it wasn’t there a few weeks ago.

2

Have you added an alert rule recently?

Antony.

3

Not exactly recently (a few weeks ago) but I suppose it’s possible there is a correlation… but I can’t see any. Here is my alert config.

grafana-rules
grafana-rules1397×1055 126 KB

4

Well, I’d say that threshold of 48 in your alert corresponds precisely with
the red line value on the left-hand Y axis.

Try temporarily changing the threshold value and see if the line moves.

I don’t know whether there’s any way to have the alert not displayed on the
graph.

Antony.

5

Oh man. I feel so dumb. You’re absolutely right.
I didn’t see that because the alert threshold concerned a value on the right Y-scale, not the left Y-scale, so it was visually nowhere near the value where it would have made sense.
I should have tried changing it anyway, the line even moves in realtime when editing the threshold field…
So the question still remains: how can I remove it, or at least make it follow the righthand Y scale? The way it is, it makes no sense at all, and I don’t want to move the voltage axis to the left.