HAProxy is a free, very fast and reliable solution offering high
availability, load balancing, and proxying for TCP and HTTP-based
applications. It is particularly suited for web sites crawling under
very high loads while needing persistence or Layer7 processing.

Note:
By default, this SlackBuild supposes that the kernel supports epoll if
the kernel release is 2.4.x.
This is a reasonable choice for running HAProxy, isn't it?
Otherwise, please remember to modify this SlackBuild.