Next, we examine the resilience of CoDoNS to sudden upheavals in the popularity of domain names. To model a flash-crowd effect, we take the DNS workload and modify the second half to reflect large scale changes in the popularity of all domain names. We achieve this by completely reversing the popularities of all the domain names in the workload. That is, the least popular name becomes the most popular name, the second least popular name becomes the second most popular name, and so on. This represents a worst case scenario for CoDoNS because records that are replicated the least suddenly need to be replicated widely, and vice versa, simulating, in essence, a set of flash crowds for the least popular records.
Figure 7 shows the median resolution latencies in CoDoNS during the flash-crowd effect introduced at the six hour mark. There is a temporary increase in the median latency of CoDoNS when flash-crowd effect starts. But, Beehive's proactive replication in the background detects the changes in popularity, adjusts the number of replicas, and decreases the lookup latency. The latency of CoDoNS after popularity reversal quickly reaches the low values in Figure 6, indicating that CoDoNS has recovered completely from the worst-case, large scale changes in popularity.