Is it possible to calculate the result of totals across multiple datapoints (rows or columns depending on how I’ve transformed things) and present the result somewhere, and perform further operations against?
I have a handful of problems I’m trying to solve that I think I can work out if I can get my head around a solution for this. And I’m not sure I’ve even asked the question right. But to give one example:
I have a series of data points for space usage in various filesystems, let’s say. For each one, I’m given the amount of space total, space used, and percentage free. I’d like to calculate the percent free across ALL of these filesystems for some sample, and display that single value in a stat panel. But they’re not all the same size. i.e.
time name space total space used percent free
2021-02-18 10:41:40 fs1 100GB 20GB 80
2021-02-18 10:41:40 fs2 200GB 20GB 90
2021-02-18 10:41:40 fs2 50GB 20GB 60
I can take the mean of all 3 “percentage free” fields, but that won’t be accurate since the FSes are different sizes. That’d give me 76.7% above, when the actual answer is 82.9%.
I can calculate the total of space total, and total of space used, but I don’t know how to then perform an operation against those results to display in my stat panel (or anywhere else).
Is this possible to do somehow? This seems like the kind of thing that would come up a lot, but so far my search-foo hasn’t found anything definitive. Nothing that was actually answered, anyway.