When Microsoft killed Windows Home Server's "Drive Extender" technology, we mourned its loss but held up hope that the company would persevere with the concept. The company has done just that with a new Windows 8 feature called Storage Spaces, described in a lengthy post to its Building Windows 8 blog.

With Storage Spaces, physical disks are grouped together into pools, and pools are then carved up into spaces, which are formatted with a regular filesystem and are used day-to-day just like regular disks.

Unlike RAID systems of old, but in common with other modern storage technologies such as Solaris' ZFS and Linux's btrfs, pools can use disks of different interface technologies—USB, SATA, Serial Attached SCSI—and different, mismatched sizes. New disks can be added to a pool at any time. Pools can also include one or more hot spares: drives allocated to a pool but kept in standby until another disk in the pool fails, at which point they spring into life.

Storage in a pool is then distributed among one or more spaces. Each space can have its own redundancy policy, with three kinds of fault tolerance offered: 2-way mirroring, 3-way mirroring, and RAID 5-like parity. With the mirrored options, a space's data is stored either twice or three times within a pool. With the parity option, the system will compute additional information and store this within the pool. If any disk in the pool fails, the data can be reconstructed using this additional information.

Spaces can be thinly provisioned, allowing the creation of spaces that are larger than the underlying pool. This allows potentially simpler management—a large "media" space for TV shows and movies could be created with some large size, say 50 TB, with only 2 TB of physical capacity in the pool. As more shows are recorded or downloaded, and space becomes tighter, additional drives can be added to the pool; the space will then use this extra capacity with no further configuration required.

The new technology appears to be superior to Windows Home Server's Drive Extender technology in just about every regard, and its integration into the core operating system indicates that it's robust enough for mainstream usage. The blog post implies that Storage Spaces are ready even for enterprise workloads, making mention of the ability to scale up to "very large-scale enterprise datacenter[s]", with pools made up of "hundreds of disks"—not a promise anyone would make of the home user-oriented Drive Extender.

Perhaps the only fly in the ointment for most home users is that in Windows 8, Storage Spaces will not be bootable. The company says that guidance will be offered on how to partition disks so that a partitioned boot disk can be added to a pool, but that straightforward booting unfortunately won't be possible. On some levels, this is unsurprising: many advanced filesystem and storage systems are not bootable in their initial version, and Storage Spaces certainly won't be the first. On the other, it would certainly be a desirable addition, as it would ensure that even if a boot disk failed, your PC would remain operational.

The first mention of Storage Spaces were made at Microsoft's BUILD conference in September 2011. At BUILD, the company did not offer significant details about the technology, and spoke of it in relation to Windows Server 8. Judging by the nature of the usage scenarios outlined in the blog post—storing videos and photographs, using USB external disks—it appears that Storage Spaces will be a feature of the desktop operating system too. We've asked Microsoft for clarification on this point.

Update: As expected, Storage Spaces will indeed be a feature of both desktop and server editions of the operating system.

If the feature does indeed ship in desktop Windows, it will overnight obsolete a range of SOHO-oriented storage systems; products like Drobo and ReadyNAS will find it hard to survive in a Windows 8 world.

• Windows 8 Consumer Preview Product Guide
  Download a detailed guide to the new and improved features in Windows 8 including AppLocker, BitLocker, Windows To Go, measured boot, and Client Hyper-V.
• Windows To Go Technical Overview
  Learn how Windows To Go can help you provide users with bootable USB storage devices containing a copy of Windows 8, along with their business apps, data, and settings.
• Frequently Asked Questions: Managing the Windows Store
  Get answers to frequently asked questions about managing end user access to, and usage of, the Windows Store within your organization.
• The Windows 8 User Experience
  Learn more about application, Web, and cloud features for end users.
• Windows 8 Consumer Preview Technical Forums
  Get help with questions on installation and setup, networking, compatibility, security, performance, and more.

As Microsoft continues to help businesses get the most out of their IT environment with new tools and solutions, today we’re making available the Diagnostics and Recovery Toolset 8 (DaRT) beta release. The DaRT 8 beta is part of the Microsoft Desktop Optimization Pack (MDOP) and provides businesses using Windows 8 with a way to be more proactive with their desktop repair procedures. Using DaRT 8, businesses can develop recovery and support plans that best fit their IT staffing and infrastructure requirements to save time and reduce challenges associated with troubleshooting and repairing system failures.

DaRT 8 beta is designed to help IT professionals easily recover PCs that have become unusable, rapidly diagnose probable causes of issues, and quickly repair unbootable or locked-out systems, all faster than the average time it takes to reimage the machine. DaRT, in partnership with a desktop recovery plan, can help businesses minimize downtime of their systems, keeping employees productive. New features specific to the DaRT 8 beta that can help IT include the ability to:

• Repair PCs instead of reimaging. The DaRT 8 beta enables IT professionals to easily recover PCs that have become unusable, rapidly diagnose probable causes of issues, and quickly repair unbootable or locked-out systems, all faster than the average time it takes to reimage the machine.     
  Use scripts to enable image creation. The DaRT 8 beta has an image creation wizard that is now built on top of PowerShell cmdlets, allowing IT departments to mount, create, apply, ad dismount and burn via scripting – ultimately letting the image creation process be saved and repurposed for later use. This kind of automation should save IT departments some time.
• Provide native support for USB media deployments. In previous versions of DaRT, additional tools were required to place DaRT images on USB drives. With DaRT 8 beta, this functionality is natively supported in the image creation wizard, minimizing the number of tools required for USB deployment.
• Create multiple images from one device. The DaRT 8 beta is able to create both 32-bit and 64-bit images on a single machine and transfer them between. 
• Choose the output format. Now as part of the image creation process, WIM and ISO output formats are supported in the DaRT 8 beta so that IT departments are sure the right format is an option for a broader deployment plan.

For more technical information on the DaRT 8 beta, please jump over to the Springboard Series Blog where Craig Ashley talks tech about DaRT’s new capabilities.

The DaRT 8 beta also supports some of the new hardware specifications that are rolling out through 2012, including support for GUID Partition Tables and the UEFI boot process, which are integral parts to Windows 8.

If you’re taking a look at the Windows 8 Consumer Preview, we encourage you to download the DaRT 8 beta. Since this is a beta version of the release, your feedback helps us determine the changes that should be made in the final version. To provide feedback simply submit your thoughts via the Microsoft Connect site.

Additionally, we are happy to announce the availability of the MDOP 2011 R2 Language Update. This release contains localized versions of DaRT 7.0 and Microsoft BitLocker Administration and Monitoring (MBAM). Languages included in this update are: English, French, German, Italian, Japanese, Korean, Portuguese (Brazilian), Russian, Simplified Chinese, Traditional Chinese, and Spanish. The MDOP 2011 R2 Language Update is available today on MSDN and TechNet and will be available to volume license customers on April 1, 2012.

For more information on MDOP, please visit www.microsoft.com/mdop.