SIRIS, ALTO, and NAS: Restoring A Thin-Provisioned Image Export To VMware ESXi with VMware Converter & Vmkfstools



This article describes the steps to restore a thin-provisioned VMDK image export to a VMware vSphere environment. There are two conversion methods you can use: VMware Converter & vmkfstools (VMware command line).

Use the VMDK / VMDK-linked export method if you need to copy the image export as thick-provisioned.

To learn more about virtual disk provisioning policies, see VMware's article on the subject (external link).


  • Datto ALTO
  • Datto SIRIS
  • VMware Converter
  • vmkfstools


To export a thin-provisioned disk image for use on VMware ESXi host:

1. Access the Datto appliance GUI.

2. Click the Restore tab.

3. Select the system to restore, and then click Export Image.

4. Choose the recovery point that you want to use, and then click Start Restore.

Figure 1: Start Restore (click to enlarge)

5. Choose the Destination. In Figure 2, the device is sending the restore to a Network Share.

6. Select VMDK as the Format.

7. Select the desired boot type: MBR, EFI, or Auto Detect.

Figure 2: Export Image (click to enlarge)

8. Click Export. The Datto appliance will create a clone of the point you selected and share it on the local network.

9. The GUI will refresh with new options. Copy either the Samba or NFS VMDK share path to your clipboard.

Figure 3: CIFS/Samba VMDK share path (click to enlarge)

10. Add the NFS share from the Datto appliance to VMware as a datastore and create the VM if necessary.

Select a conversion method to continue:

VMware Converter

1. Launch VMware Converter Standalone.

2. Log into your host and mount the VMDK export as a datastore.

3. Create a new virtual machine, and attach the VMDKs from the image export to it.

4. In VMware Converter, select the Convert Machine option.

5. Select the Powered off option, followed by VMware Infrastructure virtual machine, as shown in Figure 4.

6. Enter the host credentials. Then, click Next.

vmware.pngFigure 4: Source System wizard (click to enlarge)

7. The Source Machine page will appear. Select the newly-created VM from this list and click Next.

Figure 5: Source Machine (click to enlarge)

8. On the Destination System page, select VMware Infrastructure virtual machine from the dropdown. Enter the VMware Infrastructure server credentials in the box that populates. Click Next to continue.

Figure 6: Destination System (click to enlarge)

9. On the Destination Virtual Machine page, enter a Name value for the VM you would like to convert the disks to. The name must be unique. Click Next to continue.

Figure 7: Destination Virtual Machine (click to enlarge)

10. When prompted, select the destination host, datastore, and the virtual machine version for the VM that the converter will create.

11. On the Options page, review the selections for the conversion task. Make any edits necessary. Be sure to change the provisioning type from Thick to Thin, as shown in Figure 8. When you are ready to start the conversion, click Next.

Figure 8: Options (click to enlarge)

12. The Summary page lets you review the selections you made. Click Finish to begin the conversion.

13. The process will begin; you can monitor its progress from the main page of the VMware Converter application.

14. When the transfer completes, access your vSphere environment. Make sure that the machine's settings match the needs of your environment. Make any adjustments needed. Then, proceed to the Cleanup section of this article.


To copy the datastore from the Datto appliance to a permanent datastore on VMware with thin disk provisioning, use the following command:

vmkfstools -i /vmfs/volumes/[SourceDataStoreName]/[DriveLetter].vmdk -d thin /vmfs/volumes/[DestinationDataStoreName]/[DriveLetter].vmdk
  • The SourceDataStoreName is the datastore you created, which references the NFS share on the Datto appliance.
  • The DestinationDataStoreName is the datastore on your environment to which the disk images will be copied.


vmkfstools -i /vmfs/volumes/Datastore/C.vmdk -d thin /vmfs/volumes/HostStorage001/C.vmdk

Once the copy completes, proceed to the Cleanup section of this article to continue.


1. When the transfer completes, access your vSphere environment. Create a new virtual machine or attach the transferred disks to an existing virtual machine as necessary.

2. Make sure that the machine's settings match the needs of your environment. Make any adjustments needed.

  • If your import process requires a VMX template, and the selected snapshot originated from a protected agentless system, you can find a copy of the virtual machine's configuration, as it existed at the time of the backup, in the Image Export files. The file is named configuration.vmx. Before using this file, Datto recommends reviewing and updating its contents to ensure that the naming convention it uses, match your current production environment.
  • Attach the virtual machine's disks, starting with C.vmdk, and then any other applicable drives.

3. Boot the virtual machine. Make sure that it boots to the Windows login screen. If the virtualization fails after the first attempt, try again with a different storage controller. If the issue persists, contact Datto Technical Support.

4. After confirming that the virtual machine functions as expected, return to the Export Image screen in your Datto appliance's GUI, and click Unmount to remove the shared clone

Figure 9: Unmount image (click to enlarge)

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