LVS

LVS is described on the home page of the project as a 'load balancer'. The aim is to provide scalability for services. The main product of the LVS project is IPVS, which provides Layer-4 (transport layer) load balancing inside the kernel.

From the home page:

"IPVS implements transport-layer load balancing (layer-4 switching) inside the Linux kernel"

They also have under development Layer-7 (application level) switching inside the kernel, using KTCPVS


To provide redundancy, their are several possibilities listed on their home page.

- pirhana
- ultramonkey
- keepalived
- heartbeat + mon + coda
- heartbeat + ldirectord

I have set up a cluster using the last option. The 2nd is what nr uses.