I have a pool of 24 Windows 8.1 desktops that are used in a computer lab with Wyse thin clients. All the VDIs are stored on a single SSD array. We're using 2012 R2 datacenter as the host server and a 2012 server as the broker. After I built the 24 virtuals I had about one-third of the array left with free space. Over the course of several days the free space shrunk to less than ten percent. Eventually I ran out of disk space and had to delete a few virtuals to get things working again.

Trying to troubleshoot this I've been logging in and then out on each individual machine. This seems to release a little of the disk space. I've done this on about half and have freed up a good chunk of space. I have no idea on why the disk space is shrinking. Since each time I log into a virtual in the pool and log out the disk space increases, I'm assuming the pool is where the trouble is. Where would I start to look to determine what might be causing this?

Thanks,

Kevin

Hi Kevin,

Would you tell us how did you configure user profiles? As long as user profiles are stored on the SSD array, then I would suspect thats the cause of increasing disk space usage.

More information for you:

Easier User Data Management with User Profile Disks in Windows Server 2012

http://blogs.msdn.com/b/rds/archive/2012/11/13/easier-user-data-management-with-user-profile-disks-in-windows-server-2012.aspx

Using Hyper-V Differencing Disks with VDI

http://blogs.msdn.com/b/rds/archive/2010/10/25/using-hyper-v-differencing-disks-with-vdi.aspx

Best Regards,

Amy

Hi Amy,

I haven't configured user profiles using a file share. But my understanding is that once the user logs out of the session, the machine reverts back to the "pristine" state, so any profile info stored locally would be gone.

I did notice that I have Windows Update set to automatically download updates. When I come in on Monday, the space was very low. I logged in / logged out of every one of them and the free space returned. Do you think Updates were loaded over the weekend causing this?

I do plan to update the master and regenerate the pool making this fix.

Thanks,

Kevin

Hi Kevin,

I haven't configured user profiles using a file share. But my understanding is that once the user logs out of the session, the machine reverts back to the "pristine" state, so any profile info stored locally would be gone.

Yes, your understanding is correct.

I did notice that I have Windows Update set to automatically download updates.

If the VM is set to automatically update all the time, then there shouldnt be many updates to patch every couple of days.

I logged in / logged out of every one of them and the free space returned.

This should be the cause, since once VM is being used by users, user profiles and other system cache are taking disk space until users log out.

Best Regards,

Amy