Test was flaky because we asserted if we have 15 classes:
6 email (for each used (!!!) nodes)
6 last_net (for each used (!!!) nodes)
1 wallet
1 country ("HU")
1 empty value
But there was a very low chance to use only 5 nodes, out of the 6 (RS.Success=5, RS.Total=6).
In that specific case, we had only 12 classes, as we didn't see all the used emails, as we iterated over the used nodes only (and one node was not used).
https://github.com/storj/storj/issues/6549
Change-Id: I66882d5fa9b0d5f5b2397ea856494037972d4b81
the new bus_factor calculation doesn't make sense with different classes, as we have overlaps.
For example: it can detect a risk if we loose one country and one different subnet (with possible overlap).
It's better to calculate the stat and bus_factor per class (net, country, ...).
It also makes it easier to measure execution time per class.
Change-Id: I7d4d5f7cb811cd50c5831077b43e001908aab96b
Exemplars are representative elements for the stat. For example if a stat min is `30`, we can save one example with that value.
More details about the concept is here: https://grafana.com/docs/grafana/latest/fundamentals/exemplars/
In our context, which save the segment + position in case of min is updated, to make it easier to look after the segment in danger.
Change-Id: I19be482f1ddc7f1711e722c7b17480366d2c8312
