EFFICIENT CONNECTION SCHEDULING TECHNIQUE FOR HOSTING INTERNET SERVICES ON A CLUSTER OF SERVERS

摘要

A cluster of servers is the most promising solution to provide highly scalable and highly available network services with low implementation cost. For maximizing the performance of the cluster, an efficient TCP connection scheduling technique is required which fairly distributes the client's requests among the servers. The one of popular solutions is using dispatcher as a request distributor. However this solution has a problem that it can be the bottleneck or single-point of failure point of itself. ONE-IP, the previous work, solves this serious problem by using broadcast message for distributing the request packet in LAN. There is no central scheduling or dispatching machine. Using simple scheduling technique, in addition, the overhead due to dispatching the request is minimal. However, as ONE-IP using very simple static scheduling algorithm, it would spread the requests among servers unevenly and downgrades the cluster performance consequently. In this paper, we propose an improved TCP connection scheduling technique solving this unbalanced distributing problem. Using Round-Robin (RR) scheduling instead of hashing client's IP address, proposed technique can more evenly distribute incoming service requests among the servers. Experiments show average 3.8% improved performance in throughput compared to original ONE-IP technique.