title: System architecture for vessel management system
body: <p>I was wondering if anyone could give me some thoughts on how to best design a vessel management system with the following requirements;</p>
  
  <ol>
  <li>The system onboard the vessel gathers sensor data.</li>
  <li>The system on the vessel is mostly connected to the internet, but sometimes days without.</li>
  <li>Users need to gain access/view these data both on the vessel and onshore.</li>
  <li>Users onshore will also provide some input to the system that needs to be access on the vessel.</li>
  </ol>
  
  <p>Due to having both onshore and offshore users able to access the system when vessel is "disconnected" I have started looking into Cassandra and using the synchronization features there to keep the servers onshore and offshore synched. However, Cassandra seems to me like a bit of an over-kill for this as the amount of sensor data is not massive.</p>
  
  <p>Are there any easier ways of achieving this "appear always online" and constant availability and at the same time keep both servers/databases synched? </p>
  
  <p><a href="http://i.stack.imgur.com/SXeOh.png" rel="nofollow">Design example</a></p>