I have configured node exporter, grafana and prometheus through docker compose. I want to show Memory usage in the dashboard. I want to match the value shown with what is shown in the Ubuntu System monitor.
Below are my queries:
This is the transform:
If I turn of the transform by clicking 
button, panel gets rendered like this:
The value of 8.4 GB is correct one as my Ubuntu System Monitor shows the same. My concern is why it is not showing any gauge representing 8.4 GiB of memory is used (the same way it shows thick red gauge for Total Memory when I click that button).
Update
It started showing something. Selecting Apply to options: Memory Usage:
Selecting Apply to options: Total Memory:
In Gauge options, set
Min = 0.Your current gauge assumes the minimal value of the gauge is minimal value of current usage query.