Is Server Consolidation Beneficial to MMORPG? A Case Study of World of Warcraft

MMORPG is shown to be a killer application of Internet, with a global subscriber number increased to 17 millions in 2010. However, MMORPG servers tend to be overly provisioned because 1)such games do not have standard architectures thus dedicated hardware is assumed; 2) MMORPGs normally adopt a ``sharded design´´ to resolve the scalability challenges of content production and workload distribution; and 3) a game is commonly deployed in geographically distributed data centers to protect gamers from excessive network latencies. Therefore, an operator needs to deploy dedicated hardware for each game in each datacenter, even though hardware utilization is low. In this paper, we propose a zone-based server consolidation strategy for MMORPGs, which exploits the unique locality property of players´ interactions, to cut down the games´ considerable hardware requirement and energy use. We evaluate the effectiveness of our strategy based on a nine-month trace from a popular MMORPG World of War craft. The evaluation results show that, with a per-hour dynamic zone reallocation policy, the server number required can be reduced by 52% and the total energy consumption can be reduced by 62%, while the user-experienced latency remains undegraded.