Disk mapping does not work for dynamic disks on Windows

Products

• VMware vSphere ESXi

Issue/Introduction

Users may encounter this issue if using dynamic disks on Windows Guests.

Symptoms:

The disk mapping information that VMware Tools usually reports through GuestInfo is not available for Dynamic Disks on Windows Guests.

 

Environment

VMware vSphere ESXi

Cause

The determination of disk mapping information relies on the Windows ioctl operation IOCTL_STORAGE_QUERY_PROPERTY, which fails on dynamic disks.  This is a known issue for Windows. For more information, please refer to:

• https://community.osr.com/discussion/63013/ioctl-storage-query-property-with-dynamic-disk

Note:

• The disk mapping information is documented as provided "if known" - please refer to Data Object - GuestDiskInfo(vim.vm.GuestInfo.DiskInfo).  It may not be possible to provide it in every case, such as this.

• The dynamic disks are deprecated in Windows; please refer to Dynamic Disks for more information:

For all usages except mirror boot volumes (using a mirror volume to host the operating system), dynamic disks are deprecated. For data that requires resiliency against drive failure, use Storage Spaces, a resilient storage virtualization solution. For more info, see Storage Spaces Overview.

Microsoft's recommendation to customers using dynamic disks, other than for mirrored boot volumes, is to switch to Storage Spaces or revert to basic disks. For more information, please refer to Change a dynamic disk back to a basic disk

Resolution

Currently there is no resolution to the issue.

Workaround:

To workaround the issue, please use Storage Spaces or basic disks instead of Dynamic Disks with Windows Guests.