title: Cannot get rid of "physical connection is not usable" exception
body: <p>I am about to shoot myself. Spent few weeks now trying to solve this issue. We have an ASP.NET MVC 4 web app that uses SQL Server 2012 and Entity Framework as ORM and Unity for IoC. Web app is hosted on Amazon EC2. I started getting "Physical connection is not usable" exception. It happens few times a day. I searched many articles and forums and tried all the possible suggestions:</p>
  
  <ul>
  <li>Tried removing pooling from connection string "Polling=False"</li>
  <li>Tried limiting pool size and connection lifetime</li>
  <li>Tried changing LifetimeManager of Unity to HierarchicalLifetimeManager, PerRequestLifetimeManager. Also made sure entities context is disposed after the end of request</li>
  <li>Removed all TransactionScope references</li>
  </ul>
  
  <p>When exception happens, the only way to restore application is to restart server, which is very bad!!!</p>
  
  <p>This is full exception:</p>
  
  <p>A transport-level error has occurred when sending the request to the server. (provider: Session Provider, error: 19 - Physical connection is not usable)</p>