Advantages and Disadvantages of Distributed DBMS

Advantages

®    Data are located near the greatest demand site: The data in a distributed database system are dispersed to match business requirements that reduce the cost of data access.

®    Faster data access: End-users often work with only a locally stored subset of the company’s data.

®    Faster data processing: A distributed database system spreads out the system's workload by processing data at several sites.

®    Growth Facilitation: New sites can be added to the network without affecting the operations of other sites.

®    Improved communications: Because local sites are smaller and located closer to customers, local sites foster better communication among departments and between customers and company staff.

®    Reduced operating costs: It is more cost-effective to add workstations to a network than to update a mainframe system. Development work is done more cheaply and more quickly on low-cost PCs than on mainframes.

®    Reliability and Availability: When one of the computers fails, the workload is picked up by other workstations. Data are also distributed at multiple sites.

 

Disadvantages

®    The complexity of management and control: Applications must recognize data location, and they must be able to stitch together with data from various sites. Database administrators must have the ability to coordinate database activities to prevent database degradation due to data anomalies.

®    Technological difficulty: Data integrity, transaction management, concurrency control, security, backup, recovery, query optimization, access path selection, and so on, must all be addressed and resolved.

®    Security: The probability of security lapses increases when data are located at multiple sites. The responsibility of data management will be shared by different people at several sites.

®    Lack of standards: There are no standard communication protocols at the database level. (Although TCP/IP is the de facto standard at the network level, there is no standard at the application level.) For example, different database vendors employ different—and often incompatible—techniques to manage the distribution of data and processing in a DDBMS environment.

®    Increased storage and infrastructure requirements: Multiple copies of data are stored at different sites, thus requiring additional disk storage space.

Costs: Distributed databases require duplicated infrastructure to operate (physical location, environment, personnel, software, licensing, etc.)