VM size fills cache drive and will not empty

[iPete]

So i set up a Windows 10 VM a couple of days ago and it worked great. I set the size of the disk to be 2TB and did not think about how the cache was set up against the domains folder. So basically as I have been moving data into the VM the cache disk has been filling up and now its 100% full and the VM will not run, it gets set on pause after a very short time after starting. 

 

I since has changed the settings for domains to turn cache off, but it will not move anything off the cache. Is there any way to move this to the array? Manually starting the mover does nothing. 

 

Also is there no way to use cache with a large VM without having a huge cachedrive? 

[JorgeB]

Set the shares(s) you want moved to cache=yes, disabled the VM service and run the mover.

[itimpi]

Unraid will not span files across drives.   You therefore cannot have a VM with a vdisk whose logical size is larger than the dtive that hosts it without running into problems.

 

@JorgeB has given the steps to get files from cache to array.   Note, however, that with the vdisk on the array you are likely to take a significant performance hit when running the VM.

[iPete]

@JorgeB Thanks, your suggestion fixed the problem straight away and the mover started. Now I hope you can clarify for me: Should I now change the cache settings to off, and that will stop the use of cache for all my VMs? @itimpi So if I get this right, running a VM with a large internal drive is not an optimal solution for getting speed in the VM? This particular VM is just hosting media files, so it's not the biggest problem, if I understand you correctly, I won't be able to run other VMs off cache now? Is there a way to load one VM off the array and the rest with cache?

[itimpi]

You can always specify a specific location for a vdisk rather than letting Unraid automatically place it according to share settings.

 

since for optimum performance you want a VM to run off a fast pool external to the array maybe you are better setting up the VM you already have again with a smaller vdisk size?   You could also set it up with 2 vdisks - one smaller one on the cache/pool for the Windows system files, and a larger one on the array for other files.

 

 

[iPete]

@itimpi Thaks for that idea, I ran with that solution. I set up a new share and put a seperate vdisk there and added that to the VM as new disk. It works perfectly it seems.

 

Now I have another question. I can't seem to understand the logic behind the Unraid Cache settings. I set the new share to Cache = OFF, but it still puts everything being copied to the new vdisk through the cache disk. After copying was done, I turned off the VM and started the mover to the array. That worked, but would rather the extra disk just stayed off the cache drive all together. 

 

So what does the different cache setting actually do: OFF, Always, Prefer and only?

[itimpi]

22 minutes ago, iPete said:

So what does the different cache setting actually do: OFF, Always, Prefer and only?

There is good help built into the gUI for this setting and a more comprehensive write up here in the online documentation accessible via the ‘Manual’ link at the bottom of the GUI or the DOCS link at the top of each forum page.