Hi All,

 

I have a weird one, or at least my Google Foo is failing me. I have a Windows 10 Gaming VM running two vdisks, one for OS, one for games. The vdisks normally reside on two unassigned SSD's passed through to the VM. Somehow these vdisks have outgrown the physical space on the SSD and when I engage the drive, it pauses the VM. I moved the OS vdisk to the cache pool so that I can boot the VM, but when I do anything on the supplemental drive, it pauses.  The OS disk is supposed to be 120GB, and the gaming is 470GB.

 

Here's what the guest machine shows in Disk Management. The two SSD's are a 128GB and a 480GB. Disk Management shows that there is unallocated space because I tried shrinking the vdisk using spaceinvader's tutorial to fix this issue. What happened is the drive increased in size on the disk, no idea why.

 

This is what unassigned devices is showing, that there is no space on the SSD, but nothing else resides on it.

 

This is what is showing under the VM.

 

Lastly, this is what you see when you drill down into the directory.

 

I have seen some things about vdisks being sparse files, and that when you create them you can "Sparsify" them using fallocate, but I can't find anything on how to reduce the space back down to proper size and prevent it from happening again.

 

Any help would be greatly appreciated.

I suspect that you are getting bitten by the fact that drive manufacturers describe the capacity in decimal GB while the 

VM level is using binary GB and you have not allowed enough for this so that as a result the vdisk files really are (potentially) larger than the physical drives holding them.

 

There is also not any correlation between free space seen inside the VM and at the Unraid level.   You should always have enough space at the Unraid level to hold the full size specified for the vdisk.   You also have to alloy for the fact  that when using vdisks you have first created a file system on the drive and the control structures for that can consume some

of the space.  The fact that vdisk files are normally 'sparse' files means that you are not stopped from allocating them to be larger than the physical device holding them, but you can later run into problems when the space is actually used inside the VM.

 

In your case where you may have been better of passing through the whole physical drive to the VM rather than using a vdisk.   This would avoid the sort of problem you are currently encountering.

Edited July 20, 20196 yr by itimpi

9 hours ago, lyricalsnyper said:

have seen some things about vdisks being sparse files, and that when you create them you can "Sparsify" them using fallocate, but I can't find anything on how to reduce the space back down to proper size and prevent it from happening again.

As said, you always have to ensure that the vdisk when at its maximum size will actually fix on the drive.  But, you can do this to always have the vdisk take up the minimum amount of size required.

 

https://forums.unraid.net/topic/51703-vm-faq/#comment-557606