Should cloud database be centralized or distributed?

Distributed vs Centralized Database

• What are the pros and cons of a distributed database verses a centralized Database?

• Answer:

  Hello, theja: Well, this question has been harder to answer than I expected, but finally is here, I have focused on the features of distributed database systems and their advantages and disadvantages over centralized ones, here it is: Definition of a Distributed database http://www.webopedia.com/TERM/D/distributed_database.html "A database that consists of two or more data files located at different sites on a computer network. Because the database is distributed, different users can access it without interfering with one another. However, the DBMS must periodically synchronize the scattered databases to make sure that they all have consistent data" Here you can find a really good text about Distributed Databases: Scale Up in Distributed Databases http://www.cs.rpi.edu/~noel/distr_scaleup/distributed.html I have extracted some key phrases on Why use a distributed database over a centralized one: "A big advantage of distributed DBMSs over centralized ones is that of scalability. Growth can be sustained more gracefully in a distributed system." "Local autonomy is another reason for a business to implement a DDBMS. Since the nature of today's applications usually require data in geographic areas that are often decentralized, it often makes sense to implement a distributed system. In this way, data can physically reside nearest to where it is most often accessed, thus providing users with local control of data that they interact with." "Another reason why one might want to consider a parallel architecture is to improve reliability and availability of the data in a scalable system. In a distributed system, with some careful tact, it is possible to access some, or possibly all of the data in a failure mode if there is sufficient data replication." Another good paper about Distributed Database Systems: Emerging Technologies for Developing Distributed Database Systems http://bridge.ecn.purdue.edu/~yiguo/dropbox/w2000.pdf And here are the solutions to a test about distributed Database Systems, very useful to say in a few words what a DDBMS is: Distributed Database Systems - Solutions http://www.cs.jcu.edu.au/Subjects/cp3020/1997/Tutorials/tute8_soln.html Major features of a DDB are: * Data stored at a number of sites, each site logically single processor * Sites are interconnected by a network rather than a multiprocessor configuration * DDB is logically a single database (although each site is a database site) * DDBMS has full functionality of a DBMS * To the user, the distributed database system should appear exactly like a non-distributed database system. Advantages of distributed database systems are: * local autonomy (in enterprises that are distributed already) * improved performance (since data is stored close to where needed and a query may be split over several sites and executed in parallel) * improved reliability/availability (should one site go down) * economics * expandability * shareability Disadvantages of distributed database systems are: * complexity (greater potential for bugs in software) * cost (software development can be much more complex and therefore costly. Also, exchange of messages and additional computations involve increased overheads) * distribution of control (no single database administrator controls the DDB) * security (since the system is distributed the chances of security lapses are greater) * difficult to change (since all sites have control of their own sites) * lack of experience (enough experience is not available in developing distributed systems) Through my research I have found this book everywhere, it seems is the reference book on this subject: Principles of Distributed Database Systems (2nd Edition) http://www.amazon.com/exec/obidos/ASIN/0136597076/qid=1032285822/sr=2-1/ref=sr_2_1/104-5108104-1786302 I hope this is the information you were looking for and don't hesitate to request for any clarification. Search Strategy features "distributed database systems" -oracle -second -edition ://www.google.com/search?hl=en&ie=ISO-8859-1&q=features+%22distributed+database+systems%22+-oracle+-second+-edition+-course Regards.