In Clustered hosting, the load of hosting is spread over many machines or nodes. Basically, server clusters connect several dedicated servers to offer better efficiency, enhanced availability, and higher performance. The chance of one system affecting the performance of another is minimized. Many large websites utilize clustered hosting solutions.
An example is a large discussion forum. It will use multiple front end web servers along with many back end database servers.
Most hosting infrastructures use a single physical machine to host several hosting services, like web, mail, database, FTP, etc. However, this machine has two major drawbacks – it has a finite capacity for traffic and can be a single point of failure. This makes it an unviable proposition for a busy website or for one that experience traffic bursts. This type of hosting is quite similar to cloud hosting since the resources of several machines can be utilized by a website, which makes scalability a huge advantage to a clustered hosting solution. Also, servers can be added to the cluster as needed, which ensures flexibility to users.
A cluster host is one that is configured to assume the role of another within a cluster. The need for this type of host is because it does away with the problems associated with a single point of failure. Also, it ensures better utilization of system resources. It is basically a host machine which can lend support to another physical machine or guest operating systems. When a physical machine is down for maintenance or reboot, the cluster host can support its systems.