How can cache miss ratio be <1% but active resident ratio is only 12%?

Hey, my stats are even worse, I have a cache miss ratio of 5% and an active docs resident % of 1.21! The cluster behaves very bad, breaking often on rebalances and we’re in the process of trying to come up with the correct size to resize it to. The thing is if active docs resident does not refer to the working set is there any metric that does, since that would help getting the needed numbers for the sizing calculations?