Linux Virtual Server Tutorial

[goldenbook]

The Linux Virtual Server Project (LVS) implements layer 4 switching in the Linux Kernel. This allows TCP and UDP sessions to to be load balanced between multiple real servers. Thus it provides a way to scale Internet services beyond a single host. HTTP and HTTPS traffic for the World Wide Web is probably the most common use. Though it can also be used for more or less any service, from email to the X Windows System.
LVS itself runs on Linux, however it is able to load balance connections from end users running any operating system to real servers running any operating system. As long as the connections use TCP or UDP, LVS can be used.
LVS is very high performance. It is able to handle upwards of 100,000 simultaneous connections. It is easily able to load balance a saturated 100Mbit ethernet link using inexpensive commodity hardware. It is also able to load balance saturated 1Gbit link and beyond using higher-end commodity hardware.