title: DB design: For a website with 100 million users
body: <p>I am looking for a suggestion for a DB design not in terms of schema design but how should DB tables be distributed or spread over different servers.</p>
  
  <p>Simply putting: I have 10-15 tables for example which contain all the information of users who register.</p>
  
  <p>But if the number of users is huge (100 million+), should the DB schema be divided into different servers having db instances dedicated to store the data for different tables</p>
  
  <p>What I understand is there should be an optimal limit for the size of data that should be monitored by one DB instance. What if that optimal limit is crossed?</p>
  
  <p>Please advise.</p>
  
  <p>Regards,<br>
  Mayank</p>
  
  <p><strong>Edit:</strong>  </p>
  
  <p>Well, I would restate my question and will try to make the things clear.
  The things that came in my mind:</p>
  
  <ol>
  <li>Write a DBSchema to support the app. The app will allow user registration, status updates etc as in facebook or something  </li>
  <li>Only one DB instance will be used, which can theoritically (may be practically too by postgresql: <a href="http://www.postgresql.org/about/" rel="nofollow">http://www.postgresql.org/about/</a>) be supported.  </li>
  <li>With the increase of users just increase your server capacity. (Both harddisk and CPUs)</li>
  </ol>
  
  <p>But, as far as I understand, more the data is more time for look up.</p>
  
  <p>Moreover, all data at a central DB may not have flexibilty to spread it throughout the locations with users density.</p>
  
  <p>The different servers may not be placed regionally. So, a thought of things distributed.</p>
  
  <p>Regarding distributed DBs or filesystems I'm not comfortable as much as I'm with SQL DBs.</p>
  
  <p>So, I thought of logically distributing the tables to be monitored under different DB instances/Servers.</p>
  
  <p>I'm trying to write such an app for the first time (Never worked on DBs before :(). Please comment if what I think is weird, or my understanding of DB things are zero or anythings like that.</p>
  
  <p>I'll be highly grateful.  </p>
  
  <p>Regards,<br>
  Mayank</p>