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imageIn Windows Server 2012, a Server Message Block (SMB) file share can now store virtual machine (VM) and SQL Server resources in addition to traditional end-user files like office documents. SMB protocol is a network file sharing protocol allowing applications to read and write to files and requesting services from server programs in a computer network. Windows Server 2012 introduces the new 3.0 version of SMB protocol. A Windows Server 2012 Hyper-V host can employ SMB 3.0 file shares as shared storage for storing virtual machine (VM) configuration files, VHDs, and snapshots. Further, SMB file shares can also store user database files of a stand-alone SQL Server 2008 R2. This is a significant feature and provides a capability such that VMs or databases can be dynamically migrated. The following schematic highlights these features.


Hyper-V over SMB

A Windows Server 2012 Hyper-V host can now store virtual machine configuration files, VHDs, and snapshots in file shares over the SMB 3.0 protocol. This can be used for both stand-alone file servers and clustered file servers that use Hyper-V together with shared file storage for the cluster. This feature requires:

  • A Windows Server 2012 with the Hyper-V role or non-Microsoft file servers implementing the SMB 3.0 protocol
  • A Windows Server 2012 with the File and Storage Services role installed for hosting SMB 3.0 file share
  • A common Windows Active Directory infrastructure

SMB 3.0 file share is based on Windows security model and Active Directory infrastructure is required. And the computer account of an intended Hyper-V host employing Hyper-V over SMB will be granted access. The SMB file server must be a Windows Server 2012 with which SMB 3.0 protocol is available by default. One can also use non-Microsoft file servers that implement the SMB 3.0 protocol. For backward compatibility, Hyper-V does not block older versions of SMB, however, the Hyper-V Best Practice Analyzer (BPA) issues an alert when an older version of SMB is detected. Notice a computer that is running Hyper-V is not to be used as the file server for virtual machine storage. This forms a so-called “Loopback” configuration which is not supported.


Configuring SMB File Share

The process to create an SMB share is uneventful and with basic Windows user operations. From Server Manage, go to File and Storage Service and then click Shares of a target server as shown in the following screen capture. Here the included screen capture shows the target server RDVH is remotely accessed via Server Manager. Either form the dropdowns or simply right-clicking to bring up the menu and start the wizard for creating a new share.

add smb share

Along the process, a system administrator will specify one of the five included file share profiles. For the advanced profile, a target server must install File Share Resource Management for quota control as shown below:

file share resource management

An SMB 3.0 file share comes with various settings. A system administrator can specify Windows to enumerate items based on access control and display only those files and folders a user has permissions to access. In such case, Windows will hide a user from seeing those files the user does not have Read permission. Caching for offline access is optional and an SMB 3.0 share is also Branch Caching ready. File access with encryption is readily available and  enabled with a checkbox. The following shows a sample based on the SMB Share – Advanced profile with both caching and quota control enabled.

sample smb share

Closing Thoughts

Hyper-V over SMB signifies a newly emerging trend of cost reductions on storage hardware and a progressing standardization of storage virtualization solutions. With SMB 3.0, a storage administrator can now working on file shares instead of managing storage fabric and logical unit numbers (LUNs). The concepts and operations are directly applicable with those skill sets of Windows system administration, which reduces the overall training and operating costs. The hardware of SMB 3.0 file shares are based on existing converged network with no specialized storage networking hardware, which increases the benefits of existing networks and essentially reduces capital expenditures. The ease of provisioning and management makes storage virtualization solution a much manageable and affordable solution with long-term reductions on capital and operating expenditures.

Call to Action

  • Download and install Windows Server 2012 form and learn Hyper-V over SMB by practicing the routines.
  • Get the free ebooks from and study Windows Server 2012 and Microsoft Virtualization Solutions.
  • Register at Microsoft Virtual Academy at and complete the Windows Server 2012 track.