title: Architecture for SaaS based online portal
body: <p>We are planning to prepare a product "online clothing store" based on SaaS model.</p>
  
  <p>Different cloth vendors shall register to our portal. They will get web interface to manage own catalog of clothes.</p>
  
  <p>When end user register with the system, they can see different catalogs of different vendor.
  Of course they can do standard search, filter, sort etc on available products.
  After selection, they will order the items. Respective vendor shall get order of those items, which is selected from his catalog.</p>
  
  <p>At our end, we shall require administration panel and also customer CRM. It will keep records and data for all customers. We shall need to generate analytic about the customers. We shall record how customers are responding to different products of different vendors and according to study the behavior.</p>
  
  <p>It requires to be very scalable product. Tomorrow even if million of vendor wants to join, it should support it.</p>
  
  <p>I need advice about the architecture and overall design:</p>
  
  <ul>
  <li>What architecture should be used?</li>
  <li>Any reference system is available for consideration?</li>
  <li>Any specific design pattern, we can consider while implementing it?</li>
  <li>Any recommendation for database design?</li>
  <li>How to make sure that portal will be scalable?</li>
  </ul>