Why did my traffic shaper queue/queuedrops RRD graph data disappear
The RRD for traffic shaping graphs must be reset when a change is made to the traffic shaper settings. The RRD files are in a very specific format and refer to the number and name of the queues as they exist in the shaper configuration. Should this data change, the RRD file data becomes invalid and must be reset.
Therefore any time a traffic shaper setting is changed, the queue and queuedrops graphs are reset in order to ensure that the RRD schema matches up with the current shaper configuration.