Free Space Incorrect After Deleting Large VHDX File

[jliu79]

I have 3 Windows 2012 datacenter servers form a Hyper-V cluster.  Today I deleted a large VHDX file(500GB) from the CSV volume. In the failover cluster manager I can see the free space has increased 500GB but on Nimble it doesn't see the change at all. It still sees the same amount of free space as before I deleted the VHDX file.

[aaalders111]

Deleting files in Windows only makes changes to the MFT, logically deleting space. In order to free up that space physically the OS will need to tell the storage which blocks are no longer used and can be freed up (assuming you use thin provisioning such as Nimble does by default). This function is called TRIM or UNMAP and as far as I know this is supported in Windows 2012 for example by using the "optimize-volume" command with the -retrim parameter. Older Windows OS'es could do the same by using the sdelete tool with the -z option.

You do need to make sure the files are permanently deleted (not in the recycle bin).

[jliu79]

Thanks. I was replying to someone else in another thread. I guess moderator thought this should be a separate topic and created a new thread? Anyway someone said Windows 2012 should be able to report the free space automatically to the storage but what I found out is it doesn't.