The Research And Implementation Of Dual Hot-Standby Based On Load Balancer Of LVS

With the rapid development of Internet and society, the number of network user and web site is increasing rapidly. The availability, expansibility and security of network server are requested higher and higher. The traditional single server cannot satisfy the increasing demand. So the high availability cluster system becomes the effective way to realize the high availability of web server system, especially high availability cluster system based on Linux.Using cluster system to construct network server can make the single server cooperate with each other and finish the requested work together or provide the same service to the outside in order to improve the high availability of network.The paper researches LVS cluster of Linux open source project carefully. The conception, principle and architecture of LVS cluster are introduced in the paper. Netfilter technology of LVS and implementation of LVS are analyzed. In respect to the Load balancer of LVS cluster could become a single fault computer. Compared with variant modeling of dual computer, load balanced of LVS tolerated by duplicated hot-standby technology to improve high availability of LVS system.Basing on analysis of fault detection of duplicated hot-standby, heartbeat protocol basing on Linux kernel was proposed. The heartbeat protocol was aimed at the duplicated hot-standby. The heartbeat protocol is network protocol of TCP/IP stack. The heartbeat is different from the application process. Using heartbeat protocol to detect the fault, the heartbeat protocol didn't switch between Linux kernel layer and application layer. And application network process could finish the network communication via IP routing of IP protocol. If the heartbeat protocol could avoid them, it would reduce the running time and improve availability of the LVS. Dynamic heartbeat period of heartbeat protocol was designed. Basing on account of LVS request, heartbeat protocol sets the heartbeat period. Data backup and fault takeover of duplicated hot-standby was designed.