I am working on a application that has following  requirements :

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200 hundred branch and one head office . it financial large scale system .
that has -Accounting , cash, loan management module. Every branch operate those module .
and user hit/transaction rate is high. it is kind of banking system .
our system currently run on distributed database with Desktop application .

Now , for better maintainability , We want to run it web application server with one centralized db environment .Now , I have a confusion ,

     Q1 . is it right to transfer distributed db to one centralized db in this requirements ?

    Q2 . Actually , personally i have no working experience about distributed db , so.

         what are the real advantages distributed db over centralized db for above requirements ?   

    Q3 . is it possible to achievement performance using centralized db without distributed db for above business requirements ?