Cluster is a collection of servers, data storage systems or other hardware capacities operating as a single system. Development of networking technologies has made it possible to efficiently combine hardware, located in different sites, geographically. For example, when creating a cluster, one server can be located in Germany, the second – in the Netherlands, the third – in the United States. At the same time, for users of this infrastructure the system looks unified.
The main principle of cluster operation is redundancy. Even in case of failure of one or more network segments, the whole system will continue to work. A special software module is used for cluster management (orchestration). Orchestration mechanisms allow synchronizing data within the cluster and significantly increase the speed of data transfer.
Clusters are created not only to provide security, but also to improve system performance. While traditional network infrastructures make it difficult to accelerate computing, cluster structures make it relatively easy to increase capacity by adding new hardware resources.