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SlevinKelevra's avatar
SlevinKelevra
Copper Contributor
Jul 28, 2023

Inherited VM data disk setup query

Hi there,

 

I've inherited a VM in Azure:

 

OS Premium SSD disk of 127GB

4 x 4095 GB Standard HDD

 

In the VM the data drive totals 10.2TB with 7.6TB of space. I want to reduce the size but realize I can't, I'd have to create new smaller drives then move data to new drive letter in WIndows.

 

My confusion is why are there four identically sized disks? Also how do they only total 10.2TB when in the Windows partition manager there is no unallocated space?

 

Any suggestions if I've missed anything would be great.

 

THank you.

 

1 Reply

  • Kidd_Ip's avatar
    Kidd_Ip
    MVP
    Feb 05, 2026

    The 4 x 4,095 GB Standard HDDs have been configured within the virtual machine using Windows Disk Management, most likely as a spanned or striped dynamic volume. This configuration consolidates the individual disks into a single logical drive, which explains why the system presents a 10.2 TB volume rather than the full 16 TB of raw capacity. Azure exposes each disk independently, but Windows can aggregate them into one volume. Because all disks are allocated to this configuration, no unallocated space is visible. If a smaller capacity is required, the recommended approach is to provision new disks of the desired size, create a new volume, and migrate the data accordingly.

     

    https://learn.microsoft.com/en-us/azure/virtual-machines/windows/attach-managed-disk-portal

     

    https://learn.microsoft.com/en-us/azure/virtual-machines/disks-types

     

    https://learn.microsoft.com/en-us/windows-server/storage/storage-spaces/manage-volumes?tabs=windows-admin-center

     

     

     

     

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