Hardware Independent Bare Metal Restores using Windows Server 2008 Backup (wbadmin)

One of the most frustrating tasks for system administrators in Windows Server 2000 and 2003 is performing a restore of a server to new hardware. Nearly always the new hardware differs from the original server. If a direct restore is done from the backup (whether it be file-based or image-based), the new server often will BSOD, complaining about errors with HAL.SYS. This occurred because of driver and HAL differences between the old and new hardware.

This meant that a market developed for 3rd party solutions that enable the restore to dissimilar hardware by patching the registry and installing additional drivers before the newly restored system started. Such products, like Backup Exec System Recovery and Acronis True Image often cost upwards of $1000.

However, using the standard built-in Backup and Restore infrastructure in Windows Server 2008 and derivatives (SBS 2008 and EBS 2008), it is possible to restore an entire system to dissimilar hardware. In a presentation he gave at SMB Nation 2008, Jeff Middleton MVP stated that hardware independent restore was actually part of the design specification of Windows Server 2008.

And we tried really hard to break it. We did all sorts of ridiculous bare metal restores – from AMD to Intel, from single core to dual core to quad core, from single to dual CPUs, RAID to no RAID and vice versa.

And it worked flawlessly each time.

Our tests – restoring to dissimilar physical hardware

Windows Vista installation tests:

• Acer Aspire 1340 Laptop (AMD) > AMD Sempron Desktop

Windows Server 2008 installation tests:

• Intel Xeon Dual CPU Dual Core Server w. RAID > AMD Phenom Single CPU Quad Core Desktop
• AMD Phenom Single CPU Quad Core Desktop > Intel Xeon Dual CPU Dual Core Server w. RAID
• <3rd test – Specs to get off Linus’ Server 2008 DEV and Mel’s DEV desktop >

Test results – restoring to and from virtual hardware

For the purposes of testing virtualisation, we used the free version of VMware Server 1.0.6 – freely downloadable from the VMware website.

Windows Server 2008 installation tests:

• AMD Phenom Quad Core > VM on AMD Sempron Single Core
• VM on AMD Sempron Single Core > Intel Xeon Dual Core Dual CPU w. RAID
  
  and the reverse path:
  
  
• Intel Xeon Dual Core Dual CPU w. RAID > VM on AMD Sempron Single Core
• VM on AMD Sempron Single Core > AMD Phenom Quad Core

Conclusion

We certainly couldn’t fault the bare metal restoration features in Windows Server 2008. After conducting so many tests, we feel confident that it will work when required. Another good feature of Microsoft’s restore wizard is the "Have disk" button that allows you to load additional drivers at restore-time. This means that if you’re restoring to hardware that’s new, such as a RAID array, you can load up the drivers (especially important for RAID controllers, given that without the driver, you can’t see the disk array and thus can’t restore), perform the restoration, and then the new drivers are automatically on the newly restored system.

Well done, Microsoft!