KTCPVS 介绍
KTCPVS (Kernel TCP Virtual Server)
它可实现应用级负载平衡在Linux内核，所谓7层切换。由于架空7层开关在用户空间非常高，这是件好事，执行它的核心内，以避免间接的上下文切换和内存复制的用户空间与内核空间。虽然可扩展性KTCPVS低于IPVS
（ IP虚拟服务器） ，它是灵活的，因为要求的内容是众所周知的要求之前，将被重定向到一个服务器。
KTCPVS stands for Kernel TCP Virtual Server. It implements application-level
load balancing inside the Linux kernel, so called Layer-7 switching. Since the
overhead of layer-7 switching in user-space is very high, it is good to
implement it inside the kernel in order to avoid the overhead of context
switching and memory copying between user-space and kernel-space. Although the
scalability of KTCPVS is lower than that of IPVS (IP Virtual Server), it is
flexible, because the content of request is kNown before the request is
redirected to one server.
KTCPVS 官网
http://www.linuxvirtualserver.org/software/ktcpvs/ktcpvs.html