基于两阶段散列的Web集群服务器内容分配研究

针对Web集群服务器内容分配不均衡的问题，提出了基于两阶段散列的内容分配算法．该算法首先根据统一资源定位器字符串把服务器内容散列到k＊n个槽中，使得各槽的文件个数均衡；然后根据从Web日志中挖掘出的访问负载信息，采用分段负载互补方法把内容再次散列到孢个槽中，以使各槽内容负载均衡．同时，在集群分发过程中应用该算法，可提高请求的调度效率和节点的缓存命中率．实验结果表明，两阶段散列的负载均衡性能可比一次散列提高28．7％．

Study on Content Assignment of Web Cluster Server Based on Two-Phase Hashing

Focusing on the problem of imbalance of content assignment within Web cluster server, an efficient content assignment algorithm based on two-phase hashing is put forward. Firstly it hashes the server contents to k*n slots according to the string of uniform resource locator (URL), so as to equalize the number of files for each slot, and then hashes again the contents to n slots by the mutual complement approach of segmented load based on the access load information mined from Web log to balance the contents load of each slot. Meanwhile, applying the algorithm to the process of dispatching can improve the scheduling efficiency of requests and cache hit ratio of nodes. Experimental results show the load equilibration of the proposed algorithm is higher than that of the conventional hashing method by 28.7% on average.