LEADING OPEN SOURCE LOAD BALANCING SOFTWARE
This Apache HTTP Server module provides load balancing support for HTTP, FTP and AJP13 protocols.
At present, there are 3 load balancer scheduler algorithms available for use: Request Counting, Weighted Traffic Counting and Pending Request Counting
The Linux Virtual Server -LVS- as an advanced load balancing solution can be used to build highly scalable and highly available network services, such as scalable web, cache, mail, ftp, media and VoIP services.
Red Hat Cluster Suite provides a complete ready-to-use failover solution for high-volume open source applications, such as NFS, Samba, and Apache.
OTHER OPEN SOURCE LOAD BALANCING SOFTWARE
BalanceNG is a load balancing software running on the hardware of your choice.
Enhydra Director implements web server plugins for Apache, IIS and IPlanet supporting advanced load balancing / clustering and runtime administration. Director can be used with plain Tomcat, Jetty, JBoss, JOnAS or Enhydra Server.
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. Supporting tens of thousands of connections is clearly realistic with todays hardware.