Virtual server is a highly scalable and highly available server built on a cluster of real servers. The architecture of server cluster is fully transparent to end users, and the users interact with the cluster system as if it were only a single high-performance virtual server. Please consider the following figure.
The real servers and the load balancers may be interconnected by either high-speed LAN or by geographically dispersed WAN. The load balancers can dispatch requests to the different servers and make parallel services of the cluster to appear as a virtual service on a single IP address, and request dispatching can use IP load balancing technolgies or application-level load balancing technologies. Scalability of the system is achieved by transparently adding or removing nodes in the cluster. High availability is provided by detecting node or daemon failures and reconfiguring the system appropriately.
章文嵩博士是著名的Linux集群项目－－LVS（Linux Virtual Server）的创始人和主要开发人员。他目前是TelTel的首席科学家，从事大规模分布式的通信系统的设计和开发。他一直致力于自由软件的开发，并以此为乐。
Wensong Zhang
Chief Scientist
Dr. Zhang has extensive experience in architecting large-scale systems, system software development, system security and the Linux operating system. He is the founder and developer of the Linux Virtual Server project, which is dedicated to build advanced server clustering software for Linux.
Prior to joining TelTel, Dr. Zhang founded China Cluster Networks, a leading provider of cluster based products and services in China. Dr. Zhang also served in management roles at 21Vianet in China. A recognized expert on Linux, he is also a standing member of Co-Create Software Branch of the Chinese Software Industry Association in China.
Mr. Zhang received a Ph.D. degree in Computer Science from Changsha Institute of Technology.
http://www.linuxvirtualserver.org
[attach]7728[/attach]
