Advantages and Disadvantages of Data Replication

Advantages of Data Replication

Following are the advantages of data replication:

Reliability: If one of the sites containing the relation (or database) fails, a copy can always be found at another site without network traffic e ays. Also, available copies can all be updated as soon as transactions occur, and unavailable nodes will be u dated once the return to service.

Fast Response: Each site that has a full comes locally, so queries can be processed rapidly.

Possible Avoidance of Complicated Distributed Transaction Integrity Routines: Replicated databases are usually refreshed at scheduled intervals, so most forms of replication are used when some relaxing of synchronization across database copies is acceptable.

Node Decoupling: Each transaction may proceed without coordination across the network. Thus, if nodes are down, busy, or disconnected (e.g., in the case of mobile, personal computers), a transaction is handled when the user desires. In the place of real-time synchronization of updates, a behind-the-scenes process coordinates all data copies.

Reduced Network Traffic at Prime Time: Often updating data happens during prime business hours, when network traffic is highest and the demands for rapid response greatest. Replication, with delayed updating of copies of data, moves network traffic for sending updates to other nodes to non-prime-time hours.

Disadvantages of Data Replication

Replication has two primary Story disadvantages:

Storage Requirements: Each site that has a full copy must have the same storage capacity that would be required if the data were stored centrally. Each copy requires storage space (the cost for which is constantly decreasing), and processing time is required to update each node.

Complexity and Cost of Updating: Whenever a relation is updated, it must (eventually) updated at each site that olds a copy. Synchronizing updating in near real time can require careful coordination.