Hyper-V: VHDX-format virtual hard disks are recommended for virtual machines that have recovery history enabled in replication settings

This article is intended to provide more information about a specific issue that can be identified by running a Best Practices Analyzer scan for Hyper-V. It also can be used without running a scan, as general troubleshooting and best practice information to help you configure your server appropriately. If you have troubleshooting steps or information that would improve this article, please add it. For instructions on how to edit a TechNet Wiki article, see Wiki: How to Use the Editor.

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Note: The following sections provide details about the specific issue. Italics indicates UI text that appears in the Best Practices Analyzer tool for the specific issue.

Issue

VHD-format virtual hard disks are being used for virtual machines that are enabled for replication with recovery history.

Impact

Under some circumstances, the VHD-format virtual hard disks on the Replica server could experience consistency issues. This impacts the following virtual machines: <list of virtual machines>

Resolution

Use the VHDX format for virtual hard disks used in virtual machines that are enabled for replication with recovery history. The VHDX format has reliability mechanisms that help protect the disk from corruptions due to system power failures. You can convert a virtual hard disk from VHD format to VHDX format. However, do not convert the virtual hard disk if it is likely to be attached to an earlier release of Windows at some point. Windows releases earlier than {1} do not support the VHDX format.

Additional references