Research On Load Balancing Using Virtual Servers For DHT-based P2P Network

DHT (Distributed Hash Table) technique is applied to enable multiple nodes ofnetwork to work in combination, which can provide distributed servicescharacterized by(with) super capacity, high reliability and high availability so that ithas been adopted as main construction technology of structured P2P network.Furthermore, load-balance turns out to be a key problem that needs to be solved tomeet the required of DHT-based P2P network on stability and efficiency.Load-balance algorithm based on virtual server is a main method of structuredP2P network. But this method may lead to Single Virtual Server Problem,i.e. SVNPduring load balancing because it fails to change randomness and heterogeneity ofDHT network. Therefore, paying more attention to research and solution of SVNPwill be helpful to further improve load-balance algorithm of virtual server.This paper begins with the analysis and discussion on classical load-balancealgorithm based on virtual algorithm which indicates the SVNP existed in this kindof algorithm. Based on mathematic property of DHT network, this paper models andanalyze the process of SVNP’s happening and gives detailed probability analysisdirected against different distribution of nodes’ capability. The results show thatthere exists close relationship between probability of SVNP’s happening andheterogeneous degree of nodes when ID space of virtual servers is randomly selected.Namely, the more even the capability of nodes distribute, the lower the probabilityof SVNP becomes.Based on Above Analysis, this paper put forward a load-balance algorithmbased on splitting virtual servers to solve the inevitable SVNP when using virtualservers. This paper provides feasibility study of this algorithm, which analyzes theinfluence to DHT network after introducing split algorithm and gives thecorresponding settlement mechanism. According to the load distribution features ofthe DHT network, this paper detailed discusses the flow and implementation of thisalgorithm based on the classical dynamic DHT network load balancing algorithm,and number of issues was discussed in the initial virtual server in algorithm.Finally, this paper leverages Oversim simulation software to verify theprobability of SVNP’s happening and performance of the algorithm. Simulationresults of SVNP probability curve the probability analysis results very well, which verify the analysis of this article about the SVNP probability. Meanwhile, this paperassesses the performance of the algorithm from the nodes in the system load changes,the number of virtual servers and the communication overhead. The experimentalresults demonstrate that the split algorithm, which has no impact on the system loadbalance effect, can effectively solve the problem SVNP and significantly reduce theinitial virtual server maintenance costs.