Traditional load balancers used in server clusters have problems such as lack of flexibility, high cost, etc. To overcome these problems, research has been conducted to apply a load balancer using software-defined network (SDN) to the server cluster. Under this trend, in this paper, we proposed a hybrid load balancing method with failover capability in the server cluster using SDN. The main goal of this paper is to improve the performance and failover capability of load balancing. First, we improved the performance of the dynamic weighted random selection (DWRS) algorithm by adopting the binary search to find the target server. Next, we proposed a dynamic method with failover capability by combining the improved DWRS algorithm with a fast-failover (FF) group table. In addition, a hybrid method combining the static method using the SELECT group table and the dynamic method with failover capability is proposed to improve the performance. Finally, the failover capability and performance of the proposed method are evaluated in an experimental environment.

翻译：传统服务器集群中使用的负载均衡器存在灵活性不足、成本高等问题。为解决这些问题，研究人员尝试将基于软件定义网络（SDN）的负载均衡器应用于服务器集群。在此趋势下，本文提出了一种具有故障切换能力的混合负载均衡方法，该方法在基于SDN的服务器集群中实现。本文主要目标是提升负载均衡的性能与故障切换能力。首先，通过采用二分查找定位目标服务器，改进了动态加权随机选择（DWRS）算法的性能。其次，将改进后的DWRS算法与快速故障切换（FF）组表相结合，提出了一种具备故障切换能力的动态方法。此外，为进一步提升性能，还提出了一种混合方法，将基于SELECT组表的静态方法与具备故障切换能力的动态方法相结合。最后，在实验环境中对所提出方法的故障切换能力与性能进行了评估。