November 21, 2016

What Is Diskless Restore?

By Henry Washburn

Disaster Strikes! Your physical computer-aided manufacturing (CAM) server BSoDs because of an unanticipated Windows 10 Update and you have to present a 3D printed building design in a day. What do you do?

  1. Run around screaming

  2. Blame someone else for clicking “Yes, I want to update”

  3. Rest easy knowing that you can restore using Datto’s SIRIS Platform

Ideally, it’s number three, although one and two would be interesting to watch. as long as you have a SIRIS that can do Diskless Restores protecting you.

Datto’s Diskless Restore functionality makes it easy to overcome this type of disaster. Diskless Restore makes a previous version of the data on your CAM server’s disks accessible to the CAM server hardware directly from the Datto via iSCSI. This allows users to continue to use the server as if it was still running the operating system (OS) previous to the disastrous update and any peripherals that were attached. You can now print out the 3D rendered building design and present it to your clients. Epic Win.

That seemingly simple process is not so simple in the real world, however. Network communication is the linchpin to the whole system and up to this point, all network boot devices boot off of known hardware. How can we communicate over the network with and boot into an operating system without the operating system knowing what network card it has?

First, we had to assume that the end user was going to use the Diskless Restore with different hardware. Then we had to develop a way for your server to install and configure the network card that it sees and handoff from the BIOS to the OS. We were already well versed in editing network drivers and configurations because we have our own Hardware Independent Restore (HIR) process for Bare Metal Restores (BMRs), so we included that. Then we had to deal with the handoff. If there wasn’t a proper handoff, with Windows you would see an “INACCESSIBLE_BOOT_DEVICE” BSOD. Once we figured out a way to do handoff the communication from the BIOS to the OS for one, we had to do it over and over again for all the versions of Windows and Linux that we support.

All of that hard work is shoved into a USB stick that handles the boot environment for the hardware, the configuration of the restored OS on the Datto and the communication between BIOS and OS through iSCSI.

Try it out for yourself with the SIRIS. Use it to overcome OEM hardware licensing limitations, as those are bonded to the hardware they were initially installed on. See what kind of other solutions Diskless Restore can be used for or where you see it expanding. 

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