title: ASP.NET Server Migration
body: <p>We have a long-lived ASP.NET 3.5 application we are moving from a physical server running Windows 2005+IIS 6 to a virtual one running Windows 2008+IIS7. The new machine will assume the identify of the old one - IP's, DNS, etc.</p>
  
  <p>Our clients keep our site up for hours - sometimes even days. My fear is that when we make this switch-over, suddenly all thier viewstates will fail to validate because the MachineKey will have changed. </p>
  
  <p>Is this kind of disruption avoidable? Can I 'set' the new server's machineKey to be the same as the one in use now? I think it is autogenerated - can I find out what it is?</p>
  
  <p>Or, is this even worth it - is this a suck-it-up situation where users shouldn't expect to be able to hit a website for that long?</p>