How to Create Application Consistent Snapshots for Hyper-V
In some cases, the Hyper-V VSS writer does not create application consistent snapshots on some virtual machines (VM). As a result, the backed up data may not be in an application-consistent state.
Complete the following prerequisites to create application consistent snapshots:
- In the child VM, the integration service named Hyper-V Volume Shadow Copy Requestor is installed and running.
- The child VM is in the running state.
- The Snapshot File Location for the VM is set to the same volume in the host operating system as the VHD files for the VM.
- All volumes in the child VM are basic disks and there are no dynamic disks.
- All disks in the child VM must use a file system that supports snapshots (for example, NTFS).
Complete the following considerations to create application consistent snapshots:
- Integration Service installed in the child VM must be compatible with the Hyper-V host.
- For example: Windows 8.1/2012R2 integration service inside VM is not compatible with Windows 2008R2 Hyper-V host.
- For Windows 8, 2012 and later, and the VM running in Windows 2008R2 Hyper-V host, the Scoped Snapshot feature in the VM must be disabled. To disable the Scoped Snapshot feature, follow these steps:
- Log into the VM.
- Navigate to the following location:
- Open the SystemRestore key.
Note: Create the key if it does not exist.
- Add a 32-bit DWORD registry value named "ScopeSnapshots" and set the value as 0.
If any of the requirements are not met, the session data is crash consistent. As a result, the following features are affected:
- Backed up data that includes application data of a VM, such as SQL, Exchange, and SharePoint, may remain in a crash consistent state.
- Catalog job may fail.
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