SIRIS, ALTO, and NAS: Diskless Restore



What is Diskless Restore, and how do I use it?

NOTE: This option is unavailable for SIRIS Private replicated snapshots.


  • Datto SIRIS
  • Datto ALTO


Diskless Restore is an alternate method of performing a virtualization of a system backed up to a SIRIS or ALTO. Instead of virtualizing a recovery point directly from the Datto appliance, you can virtualize from any target hardware capable of booting from a USB stick. The imaged USB stick uses iPXE on the network card of the local machine to boot, and then virtualizes the recovery point from the Datto appliance. You can use this method of recovery when you don't want to use up the resources (RAM, CPUs) of your Datto appliance for the virtualization.

Note: Legacy Windows systems (Pre-Vista) are not supported.

Network implications of iPXE

Since diskless restore uses your network card to boot, we highly recommend that you have two network cards on the target system. Also, when you boot, the VM will use DHCP to assign an IP address on your local LAN. There is no way to change this setting.

If you have trouble performing a diskless restore using your primay NIC, try switching to the secondary NIC.

Use Cases

If a server goes down due to hardware failure, and you expect a lengthy downtime, you should consider diskless restore as an alternative to virtualization if:

  • The amount of resources needed by the virtualization would be prohibitive to allocate on the Datto appliance.
  • You need a higher level of performance than what the virtualization can deliver on the Datto appliance.
  • You have spare hardware that is available for you to temporarily image as a production machine.

If you choose to back up the diskless restored machine to your Datto appliance, you will be able to use its backups to perform a USB Bare Metal Restore or a ShadowProtect Bare Metal Restore to the original hardware after you have restored it.

NOTE: Diskless Restore for ReFS is currently unsupported. Any ReFS volumes in the selected snapshot will be excluded from the restore. To perform a restore of an ReFS volume, use the Volume Restore feature.


Diskless Restore now shows up as a Recovery Type, as shown in Figure 1.

Figure 1 - Restore from Backup

Connect a USB drive to your Datto appliance. Select Diskless Restore, give the drive a Label, and choose the security level of the USB boot disk. These options provide you with a method to control how the USB boot drive can be used.

  • Standard allows the user to select any system and any recovery point.
  • Whitelist allows the user to select specific systems to be booted with the recovery USB.
  • Direct allows only a specific system and recovery point.

Then, select the USB drive to image. To prevent overwriting an internal disk, you will only see detachable drives in this list.

Then, click Image USB.

When the process is complete, the button changes to Configure.

Figure 2 - Configure

Click the Configure button to view details about the imaged disk or to de-provision the disk.

Figure 3 - Details and Deprovision

Now that the disk is imaged, you can connect it to a target machine and boot from it. The imaged OS uses the target hardware to connect to the Datto appliance. Depending on the configured security settings, you can then choose which machine and/or recovery point to boot from.

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