We recently installed a VMWare/Dell VXRail deployment at my work to replace older ESXi 6.5 servers. I’m transitioning existing systems in the server room to the new VXRail through physical-to-virtual (P2V) or virtual-to-virtual (V2V) migrations. Since VMWare has removed their standalone converter, I’m using Veeam for the P2V.
I had an issue a couple of days ago where I performed a P2V as usual, but the VM was showing up with thick provisioned disks on the vSAN, instead of thin provisioned ones, as the assigned storage policy mandates. I was alerted to this by a vSAN online health check, as the “Thick-provisioned VMs on vSAN” alert tripped. This alarm triggers when vSAN detects thick-provisioned VMs, which in my case was occurring despite the presence of Object Space Reservation = 0 (thin provisioned) in the applied vSAN Storage Policy.provisioned.
There is no way in ESXi 7 to forcibly re-apply the currently-assigned storage policy, so I fixed this by cloning the existing policy, applying that, then reapplying the original policy again.
- Open the Policies and Profiles menu, and select VM Storage Policies.
- Select the existing vSAN storage policy and click Clone. We’ll create an exact copy of the existing profile and apply it to the problem disks.
- Assign a new name. I appended “Clone” to the end of my existing policy name. Press Next.
- There is nothing to change under 2 Policy Structure. Press Next.
- Under 3 vSAN, select the Advanced Policy Rules tab. Ensure that Object Space Reservation = Thin Provisioning. Press Next.
- There is nothing to change under 4 Storage Compatibility. Press Next.
- There is nothing to change under 5 Review and Finish. Verify that Object Space Reservation = Thin Provisioning. Press Finish.
Right-click the VM that has Thick Provisioned disks, select VM Policies > Edit VM Storage Policies. Change the applied Storage Policy to the newly created one. After selecting the new policy, the edit policy wizard will display the change (decrease) in storage consumption. Click OK to apply the change.
Wait for the policy to apply, which could take 10-15 minutes, depending on the size of your disks. The disk should now show that it’s Thin Provisioned.
After this is complete, reapply the original policy.