Why does the original home directory of my virtual machine still exists after a storage vMotion?

Last weekend I implemented a new storage DRS cluster for a customer of mine. I must say, storage DRS rocks! But this is off topic for this post. If you want to know more in depth storage DRS stuff. Check Frank Denneman website.

After I implemented the storage DRS cluster I wanted to move about 60 virtual machines onto the new datastore cluster. These virtual machines where all Windows 7 virtual machines because the customer runs VMware View. So I selected the blue folder where the virtual machines resides and sorted the view on power state. First I selected the power off virtual machines and initiated a migration to the new datastore cluster. Second I selected the powered on virtual machines and also initiated a migration to the new datastore cluster. Then it was off to bed.

The next morning I check the result finding that about 20% of the virtual machines where not moved and that about 5% of the virtual machines where move according to vCenter but when I checked the datastore browser I still saw the original virtual machine home directory.
After some investigation where problem was 2 sided.

Storage vMotion doesn’t migrate all of the files that are in the virtual machine home directory.
Only files that native belong to a virtual machine are migrated to the destination. In my case the customer experimented with creating a screenshot of a virtual machine. This option makes a .png file in the virtual machine home directory. A storage vMotion doesn’t migrate the kind of file, so in the final phase of a storage vMotion the virtual machine files are deleted on the original datastore but not the ‘non-native’ file, making the deletion of the original virtual machine home directory impossible.

Because off performance reasons I can imaging that VMware only migrate ‘native’ virtual machines file. Imaging that somebody accidentally places a 8 GB DVD ISO file in the virtual machine  home directory.  That file is also migrated. On the other hand, maybe I wanted these kind of files in the virtual  machine home directory. And know these file aren’t migrated. And how many of  the VMware administrators check if the original home directory is really deleted on the original datastore? Not many I guess.
I think it would be nice it VMware changes this in the next update or release.

Power state changed while waiting for a storage migration
The virtual machines where Windows 7 virtual machines because the customer runs VMware View. The maximum total concurrent storage vMotion is 6. As I wanted to move 50 virtual machines 44 had to wait. During this wait period, the View broker powered down several virtual machines because the user logged out.

I noticed this behavior before when I use scheduled tasks in vCenter. I’m not sure why vSphere doesn’t check the power state of a virtual machine again when it started migration. For me it doesn’t matter if the machine is powered on or powered off. I just wanted it to be migrated to the destination. This makes storage vMotion a bit less usable for migrations of many virtual machines at the same time that change power state now and than.
Never the less I find storage vMotion a great tool! But in combination with VMware View……..?

About Michael
Michael Wilmsen is a experienced VMware Architect with more than 20 years in the IT industry. Main focus is VMware vSphere, Horizon View and Hyper Converged with a deep interest into performance and architecture. Michael is VCDX 210 certified, has been rewarded with the vExpert title from 2011, Nutanix Tech Champion and a Nutanix Platform Professional.

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