title: Updating the production IIS WebSite and SQL Server Database without stopping
body: <p>There is a testing server that uses the testing database. We test the website on the testing server. If it is okay, we update the website and the database schema from the testing server to the production server. But this method is very painful and risky. </p>
  
  <p>First, we have to redirect the users to a maintenance page, so the website is paused for a while. </p>
  
  <p>Second, if something goes wrong when updating, we have to back to old website, because we can't put the website in a maintenance mode for a long time. </p>
  
  <p>So I'm seeking a solid solution to update an IIS website and an Sql Server Database without data loss and using maintenance mode. Is there any way to do this? How the big websites do this without data loss and pausing. </p>
  
  <p>We've thought using a release candidate website. We've planned to use this RC website for temporary. First, we update the RC site, then swap the bindings between RC and production website. But this time the database is problem. Because we can change the database schema, and the old one can't work with new database. So, if we use a temp site with temp db, there will be data loss. Also, the updated website won't work with old database if the temp site uses old production database. So I need a solid and practical solution for this problem.</p>