Research Of Load Scheduling Mechanism On Linux Cluster

With the rapid development of network and increasing of internet users, the single server can not satisfy the requirements of A large number of users, and the emergence of cluster solves the problem.It is scalable,cost-effective, high-availability,, so it has been widely used. Load balance is the key factor improving the performance of cluster, and it has a high research value and application foreground,which is a hot spot of cluster research.This paper is one important part of project, which is supported by Dalian Science and Technology Funds"a new web server resource management and system status monitoring (No: 2005 J22JH031)".The paper mainly researches the load balancing of Linux cluster. Firstly, it introduces the cluster load balancing algorithms model, load indicators, scheduling algorithms, load balancing technology. Secondly, it expounds the LVS architecture, software level ,and focuses on the four types of commonly used algorithms and the forwarding of IP-based Layer.At present, the LVS cluster scheduling algorithm is still load scheduling without feedback,which is adapt to a small number of users accessing.But to large-scale accessing ,LVS has the problems of low efficiency, poor stability, poor availability,which make the whole performance decline.Finally,basing on the analyses of the original scheduling algorithm's deficiencies, the paper proposes and builds a cluster load dynamic scheduling scheme(LBDW) with feedback.LBDW calculates dynamic load weight by collecting load information, estimates the servers'remainder capacity, monitores the servers'health status, and then selects one weighted scheduling algorithm to achieve dynamic load scheduling. This paper optimizes the Dynamic Weighted Least-Connection (DWLC) algorithm,makes DWLC into Optimizing Dynamic Weighted Connection(ODWC) algorithm, and applies ODWC to the cluster dynamic scheduling programmes with feedback.The test tool Siege tests the scheduling algorithms WLC, DWLC and ODWC. The results show that in the case of the same cluster load, the ODWC algorithm is better than the DWLC, especially in a short period of time,the advantage is more obviously. And the dynamic scheduling algorithm DWLC performs better than static scheduling algorithm WLC, especially in the case of large load.