Support policy for Microsoft SQL Server products that are running on a virtual machine in a Windows Server 2008 Hyper-V environment
Microsoft SQL Server 2008
Microsoft supports and provides technical help to customers who run SQL Server 2008 on a virtual machine in a Windows Server 2008 Hyper-V environment except for certain configurations that are documented in the
Hardware and Software Requirements for Installing SQL Server 2008 section of the
SQL Server 2008 Online Book.
Microsoft SQL Server 2005
SQL Server 2005 is not fully supported on a virtual machine in a Windows Server 2008 Hyper-V environment.
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http://support.microsoft.com/kb/956893