UM cluster is working of quorum(more than 50% of servers in the cluster) must be active and intercommunicating to each other. Quorum is the term used to describe the state of a fully formed cluster with an elected master and other is slaves.
In this approach you can configure a cluster with 3 servers and recommended for high availability , load balancing and scalability.
In Other approach you can configure a cluster with 2 servers . The quorum rule availability of more than 50% of servers in the cluster is achieved by defining the server in two sites(primary and backup) and by allocating additional flag “isPrime” is one of these sites.
The value of the IsPrime flag in a site indicates whether the primary site or the backup site as a whole can cast an additional flag. The failover is automatic if the site where the IsPrime flag is set to false fails. If the site where the IsPrime flag is set to true fails, you need to manually set the IsPrime flag to true on the active site and perform manual failover.
Above aproche known as Active/Active Clustering.
As Senthil advised youcan use Enterprise manager which is an admin UI for UM monitoring and delete, create any assets through enterprise manager.