Hyper-v VHDX and AVHDX total size exceeds maximum provisioned size

Question

Hey all. I'm hoping someone can educate me a bit. I've inherited a Hyper-V cluster and have a VM with a hard drive that is provisioned at 2.78TB. When I look at the hard drive files, I see a VHDX file at 1.02TB and an associated AVHDX file at 1.86TB. I'd like to merge the two, but it appears that the total space for the VHDX and AVHDX exceed 2.78TB.

The VM itself reports 336GB of free space of 2.78TB. My thought is that it will likely merge fine, but it gives me some pause that the total file size for the VHDX and AVHDX exceed the provisioned amount. Is this because the AVHDX is tracking all the changes since checkpoint was created? When they are merged, the file should trim back down to it's current "real" size?

Hopefully that is clear. Please let me know if it needs some clarification.

Answer 1

Hello

Thank you for your question and reaching out. I can understand you are having query\issues related to Hyper-V VM

It may happen if you have VM with Dynamic Disk allocation

Please try to shrink the VM size and to the lowest possible or Export the VM to different location having enough disk size.

It might be that you have used more disk space at some point, and now you only use about 170GB of disk space, dynamically expanding virtual disks (VHD/VHDX) will grow as needed, but they will not release any space even if you delete data from the disk.

If you want to reduce the upper size limit of your VHDX you would need to shrink the VHDX disk.
To shrink a VHDX you can use the Resize-VHD PowerShell cmdlet.

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