Web cluster systems consist of a load balancer for distributing web requests and loads to several servers, and real servers for processing web requests. Previous load distribution scheduling algorithms of web cluster systems to distribute web requests to real servers are Round-Robin, Weighted Round-Robin, Least-Connection and Weighted Least-Connection(WLC) algorithm. The WLC scheduling algorithm, in which a throughput weight is assigned to real servers and the least connected real server is selected for processing web requests, is generally used for web cluster systems. When a new real server is added to a web cluster system with many simultaneous users, previous WLC scheduling algorithm assigns web requests to only the new real server, and makes load imbalance among real servers. In this paper, we propose a improved WLC scheduling algorithm which maintains load balance among real servers by avoiding web requests being assigned to only a new real server. When web requests are continuously assigned to only a new real server more than the maximum continuous allocation number(L), the proposed algorithm excepts the new real server from activated real server scheduling list and deactivates the new real server. And after L-1 allocation round times, the new real server is included into real server scheduling list by activating it. When a new real server is added to web cluster systems, the proposed algorithm maintains load balance among real servers by avoiding overloads of the new real server.
[1]
Chun-Kyun Youn.
A Load Distribution Technique of Web Clustering System based on the Real Time Status of Real Server
,
2005
.
[2]
Dejun Mu,et al.
Proportional Delay Differentiation Service and Load Balancing in Web Cluster Systems
,
2010,
2010 INFOCOM IEEE Conference on Computer Communications Workshops.
[3]
Hai Jin,et al.
HARTs: high availability cluster architecture with redundant TCP stacks
,
2003,
Conference Proceedings of the 2003 IEEE International Performance, Computing, and Communications Conference, 2003..
[4]
Alexei Kuzmin,et al.
CLUSTER APPROACH TO HIGH PERFORMANCE COMPUTING
,
2003
.
[5]
Sascha Ossowski,et al.
Proceedings of the 2010 ACM Symposium on Applied Computing (SAC), Sierre, Switzerland, March 22-26, 2010
,
2010,
SAC.
[6]
Kim Seok-chan,et al.
System Infrastructure of Efficient Web Cluster System to Decrease the Response Time using the Load Distribution Algorithm
,
2004
.
[7]
Daniel Mossé,et al.
Load forecasting applied to soft real-time web clusters
,
2010,
SAC '10.
[8]
Wensong Zhang.
Linux Virtual Server for Scalable Network Services
,
2000
.