Replication is a set of technologies for copying and distributing data from one database server to another server and then synchronizing between databases to maintain consistency and avoid data loss

Master Slave :Master/slave or primary/replica is a model of communication where one device or process has unidirectional control over one or more other devices. In some systems a master is selected from a group of eligible devices, with the other devices acting in the role of slaves.

Multi Master : Multi-master replication is a method of database replication which allows data to be stored by a group of computers, and updated by any member of the group.

Features of Data Replication

Availability

Queries (involving relation R) can be continued to be processed in spite of the failure of one site.queries (involving relation R) can be continued to be processed in spite of the failure of one site.

Increased parallelism

The sites containing relation R can process queries (involving relation R) in parallel This leads to faster query execution.

Speed

The more replicas of, a relation are there, the greater are the chances that the required data is found where the transaction is executing and reduces movement of data among sites & increases speed of processing

Balanced Load

Optimize workload distribution across multiple computing resources, making them individually more resilient to activity spikes that would otherwise cause slowdowns and other disruptions

High availability

System’s ability to avoid loss of service by minimizing downtime. It’s expressed in terms of a system’s uptime, as a percentage of total running time as 99.999% uptime.

Backup & DR Plans

Ensuring that all the information and data in a business that could have been lost is recovered from site Backup & database replications so as to assist in future needs.