Clustering refers to a group of servers that combine processor power, RAM, storage capacity, and network interfaces to achieve the high availability of services. Clustering recognizes the two most common practices:
- Fail-over clustering: It requires a minimum of two servers, and works on the active-passive principle, where one server is active and the other server is passive. Usually, it is applied to databases, mail servers, and in general, backend processing environments.
- Load-balancing clustering: It requires a minimum of two servers as well; however, servers are merged into one virtual server exchanging heartbeats. As far as users are concerned, they access a single server; as far as back-end processing is concerned, ...