I know this topic is somewhat advanced for some of you, but for others hopefully this will be useful. So what is a load balancer? To better understand the term, let me explain to you a bit the meaning of load balancing.

In computing, particularly networking, load balancing is defined as evenly sharing the amount of work or load between two or more computers, network links, CPUs, or other resources in order to achieve optimum resource utilization, maximize throughput, decrease response time, and increase reliability thus maximizing uptime. Load balancing is typically utilized to moderate internal communications in computer clusters.

There are several popular open source load balancers or load balancing software applications for Linux, which can be used with almost any kind of service, including FTP, HTTP, DNS, SMTP, POP/IMAP, VoIP, etc.

Here are some of them: