Very odd - notice how the latency is high when the read IOPS are low. When the read IOPS climb, 95th percentile latency drops.
Looks like there is a constant rate of high latency requests, and when the read IOPS climb, that constant rate moves to a higher quantile. I'd inspect the raw results but they're quite big: https://github.com/scylladb/diskplorer/blob/master/latency-m...