Cluster is a group of servers that appears as single
unit to the client.
The advantages of a clusters are
1. Scalability : There are more servers to process requests. It is possible to add more servers without any client interruptions.
2.High avaliablity : This arises because of redundancy. If one of the servers in the cluster fails another one can take over.
Load balacing is a means of distributing client request among the servers in the cluster. We make of algorithms like DNS ROUND ROBIN, Hard ware load balancing for load balancing.