I spent 2 work days doing a trial upgrade from Windows Server 2008 R2 to Windows Server 2012.  It takes one hour or so to upgrade a Windows Server 2008 R2 box and a couple of hours to apply the latest Windows Updates. As you can expect, much much time ticks when you dive into the upgrade. So, DO a good planning before you go. The following is my trial notes:

• SCVMM 2008 R2 SP1 on Windows Server 2008 R2
  • Remote Desktop related service are not allowed
  • All the original languages are removed after upgrade
  • ASUS XGI Volari Display driver for Windows Server 2012 is not available
  • SCVMM 2008 R2 failed after upgrade because of compatibility.
    SCVMM 2012 SP1 is the only version that supports Windows Server 2012.
  • Windows update terribly failed and keeps rebooting and recovering. See the pciture below.
    DO NOT apply any windows update after upgrade if any compatibility concerns exist.
• IIS 7.5 on Windows Server 2008 R2
  • The service of SQL Server 2008 R2 is unexpectedly disabled after upgrade
  • log4net UDP components failed. The communication between web application and local log4net console process was missing. No log was sent to the log4net console as a UDP server.
  • Windows update item, KB2770917, failed.
• TFS 2010 on Windows Server 2008 R2
  • The new features of TFS 2012 are not attractive enough
  • ALM is enhanced but this is not enough for me to upgrade to TFS 2012 that is running on the old Windows Server 2008 R2 box.