Clusters are sets of collaborating computer systems that are usually used to guarantee high availability of services. Here's an example: You have your Oracle database and you need to make sure that this database service is available at all times (e.g. because your business depends on it). Then it would be foolish to just install Oracle on one single server. Because that server may break or something like that. In order to make sure that the Oracle service is still working even if a server fails, you simple install Oracle on a second server and connect it to the first one.
In return you get a highly available Oracle service which does not break down even if one of your servers gives up.
In real life it's a bit more complicated (keywords you may want to look up: Heartbeat, Witness, Log shipping, Active/passive fail over, Load balancing, Replication).
In return you get a highly available Oracle service which does not break down even if one of your servers gives up.
In real life it's a bit more complicated (keywords you may want to look up: Heartbeat, Witness, Log shipping, Active/passive fail over, Load balancing, Replication).
