LVS four layer load balancing cluster (5) LVS overview

LVS - Linux Virtual Server,Linux Virtual server

The basic idea of load balancing is ： Balance the load as much as possible in a server cluster . The usual approach is to set up a load balancer on the front end of the server （ It is usually a special hardware device ）. The load balancer then routes the requested connection to the most idle available server . The following figure shows a typical load balancing setup for a large web site , One of the load balancers is used for HTTP Traffic , Another one for MySQL visit .

Load balancing has 5 A common purpose .

（1） Extensibility ： Load balancing is helpful for some scaling strategies , For example, read data from the standby database during read / write separation .

（2） Efficiency ： Load balancing helps to use resources more efficiently , Because it can control where requests are routed .

（3） Usability ： A flexible load balancing solution can use servers that are always available .

（4） transparency ： The client does not need to know whether load balancing settings exist , It doesn't matter how many machines are behind the load balancer , What's the name . The load balancer shows the client only a virtual server .

（5） Uniformity ： If the application is stateful （ Database transactions 、 Website conversation, etc ）, Then the load balancer should point related queries to the same server , To prevent data loss . The application does not need to track which server it is connected to .