Introduction

HAProxy Overview

HAProxy is a free and open source piece of software written in C language. It provides high availability, load balancing, and application proxy based on TCP and HTTP. HAProxy implements an event-driven, single-process model that supports tens of thousands of concurrent connections. Its operation mode allows it to be easily and safely integrated into your current architecture, while protecting your web servers from being exposed to the network. Multiprocess or multithreaded models are limited by memory, system schedulers, and locks, and they rarely handle thousands of concurrent connections. Event-driven models do not have these problems because they can manage resource and times better. However, they have a poor availability on multi-core systems. They have to be optimized for each CPU time slice (Cycle) to do more work. HAProxy is especially suited to web sites that are heavily loaded and often require session maintenance or seven-tier processing.

Programming language: C

Brief description: web load balancer

Recommended Version

HAProxy 1.9.0

This document applies to HAProxy 1.9.0. It also provides reference for porting of other HAProxy versions.