A Replication Strategy Based on Optimal Load Balancing for a Heterogeneous Distributed Caching System in Networked GISs

Networked geospatial information services in cloud-based environments are distributed and heterogeneous; accesses to geospatial data (tiles) are uneven and has the feature of a high degree of aggregation. Aiming to minimize the degree of load imbalance, this paper proposes a replication strategy for a heterogeneous distributed high-speed cluster-based caching system. First, taking into account the unbalanced accesses to tiles, it minimizes the weighted communication values of hotspot tiles, and generates the maximum number of replicas based on the total cache capability of the distributed cluster-based caching system. Then, since each server has a different processing capacity in the heterogeneous system, the strategy places the replicas based on the service performance of each caching server and the weighted communication value of each replica, thus matching the cache capacity of each server. Experimental results reveal that the proposed strategy can avoid server congestion while fully utilizing limited cache capacity to achieve a better load balancing and a high resource utilization, delivering good response performance and a high cache hit rate.