Advantages and Disadvantages of Distributed Databases over Centralized Databases / Relative Advantages of Distributed Databases / Disadvantages of Distributed Databases / Discuss the Advantages and Disadvantages of Distributed Databases / Advantages of Distributed Databases compared to Centralized Databases / Advantages and Disadvantages of Distributed Database Management System / Advantages and Disadvantages of Distributed Database System over Centralized Database System
Advantages of Distributed Database System
1. Increased reliability and
availability – A distributed database system is robust to failure to some
extent. Hence, it is reliable when compared to a Centralized database system.
2. Local control – The data is
distributed in such a way that every portion of it is local to some sites (servers).
The site in which the portion of data is stored is the owner of the data.
3. Modular growth (resilient) –
Growth is easier. We do not need to interrupt any of the functioning sites to
introduce (add) a new site. Hence, the expansion of the whole system is easier. Removal of site is also does not cause much problems.
4. Lower communication costs (More
Economical) – Data are distributed in such a way that they are available near
to the location where they are needed more. This reduces the communication cost
much more compared to a centralized system.
5. Faster response – Most of the
data are local and in close proximity to where they are needed. Hence, the
requests can be answered quickly compared to a centralized system.
6. Reflects the organizational
structure – Normally, database is fragmented into various locations wherever we
have controls.
7. Secured management of
distributed data – Various transparencies like network transparency,
fragmentation transparency, and replication transparency are implemented to
hide the actual implementation details of the whole distributed system. In such
way, Distributed database provides security for data.
8. Robust – The system is continued
to work in case of failures. For example, replicated distributed database
performs in spite of failure of other sites.
9. Complied with ACID properties –
Distributed transactions demands Atomicity, Consistency, Isolation, and
Reliability.
10. Improved performance and
Parallelism in executing transactions can be achieved.
Disadvantages of Distributed Database Systems
1. Complex Software – Complex implementation.
Costs more in terms of software cost compared to a centralized system. Additional
software might be needed in most of the cases over a centralized system.
2. Increased Processing overhead – It costs
many messages to be shared between sites to complete a distributed transaction.
3. Data integrity – Data integrity
becomes complex. Too much network resources may be used.
4. Different data formats might
be used – This may cost time.
5. Deadlock is difficult to
handle compared to a centralized system.
6. May cause much more network
traffic in case of write operation in a replicated form of distributed
database.
7. Distributed System supported
Operating System is required to implement distributed database system.
8. The data shared between sites
over networks are vulnerable to attack. Hence, network oriented security
protocols to be used based on the sensitivity of data shared.
9. More complex in terms database
design – According to various applications, we may need to fragment a database,
or replicate a database or both.
10. Handling failures is a
difficult task. In some cases, we may not distinguish site failure, network
partition, and link failure.