Back in April we dissected Drive Extender v2 – Microsoft’s storage pool and data duplication technology for Windows Home Server – based upon the first preview release of Windows Home Server “Vail”. In “Vail”, Microsoft was going to significantly overhaul this cornerstone piece of technology for WHS, replacing the file-centric Drive Extender v1 with the block-centric Drive Extender v2. In a nutshell DE v2 was intended to fully modernize the underpinnings of Drive Extender by bringing it closer to contemporary peers like ZFS, and in turn bringing with it a number of performance, compatibility, and data reliability benefits.

With such a change would also come some drawbacks compared to the existing implementation of Drive Extender, but it’s nothing we expected Microsoft wouldn’t be able to surmount. Certainly everything seems to have been firing on all cylinders over at Microsoft, as WHS “Vail” was joined by 2 additional business-focused WHS offshoots, Windows Storage Server 2008 R2 Essentials and Windows Small Business Server 2011 Essentials.

So imagine our utter shock when we found out that Microsoft is going to be removing Drive Extender entirely from “Vail” and the rest of its offshoots. Effective immediately, Microsoft is dropping Drive Extender from all of these second-generation WHS operating systems, and instead will be releasing these OSes without a native storage pool/duplication feature.

Ultimately Microsoft is citing the feedback based on the potential drawbacks of DE v2 such as the inability for other OSes to read DE v2 disks, and what Microsoft believes is a diminished need for DE with the availability of 2TB+ hard drives. The needs of “Vail’s” two business-class offshoots may have also played a part, as Microsoft notes that “our development for these products is very closely tied, a decision like this affects all three.” What we can easily imagine however is that DE v2 development was not going as well for Microsoft as they hoped, as OS programmers and drive makers alike can tell you just how difficult it is to design a new product/filesystem while avoiding corruption – even Microsoft got it wrong the first time. DE v2 by extension was going to be pushing the envelope as far as what any consumer filesystem was capable of.

In any case at this point we’re still trying to scoop our jaws off of the floor. Drive Extender is by no means the only major feature of Windows Home Server – least we forget remote access and client backups – but it’s certainly a cornerstone of the OS and goes hand-in-hand with the OS’s file server capabilities. The loss of DE further blurs the line between WHS and Linux, not to mention reduces the separation between it and dedicated NAS boxes.

Ultimately however this is only the beginning of the story for WHS “Vail”; Microsoft has made it clear there’s still a great deal to discuss about “Vail” at CES next year, so hopefully by then we won’t be left scratching our heads at where exactly Microsoft is going with the next iteration of their Home Server line of OSes.



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  • NeonFlak - Friday, November 26, 2010 - link

    I guess I can thank MS for helping me to save some money. I was going to upgrade my three WHS boxes to VAIL. Guess I'll be holding onto WHS as long as possible now. Reply
  • gaspard - Friday, November 26, 2010 - link

    I can see where they were going but I personally believe that the first version with the software stack ABOVE NTFS is the way to go, this way you can rip out a HDD and read the files on it normally.

    If you're using Linux you can pick up a FUSE filesystem called MHDDFS (Yes catchy name I know) which basically does the same thing, spreading files across multiple HDDs seamlessly, whilst retaining the individuality of the drives, so you can then pull one out and it has all of it's files intact, the beauty of MHDDFS is that it works with any supported File system, even NTFS...

    So this was the one feature that interested me about WHS... I guess I'll just be installing a lightweight Linux distro on any future file servers of mine, doh...

    I have not seen a similar file-level drive splitting feature for windows, except for WHS...
    There is one called FlexRAID (

    But it was complex to setup in comparison to MHDDFS, when you just want multiple drives combined.

    I guess it depends on what your storage goals are...
  • bedwyr - Monday, November 29, 2010 - link

    Count me in as another person who is happy with the removal of DE v2. I tried both of the public previews and was unhappy with both. If DE v2 was more like ZFS I would have been happy but thats not what it is.

    The way DE v2 was implemented made it a hog 66% of drive space gone right off the bat. 50% for duplication and almost 16% for CRC. Along with terrible performance.

    I don't understand how so many people are upset by the removal of DE v2. The most active topics about Vail on Microsoft connect is about how DE v2 is a deal breaker (as in if DE is in I'm out).

    I left Vail after a month of fiddling with it. With DE gone I might come back. A true ZFS type of file system would be great if microsoft could actually bring it to the table.
  • LoneWolf15 - Monday, November 29, 2010 - link

    "I don't understand how so many people are upset by the removal of DE v2. "

    People are unhappy by the removal of DE ENTIRELY, not by the removal of DE v2.

    Most people would be very happy just to have DE v1 back in Vail. And, a lot of people in technical forums need to remember, the big thing about Drive Extender is that almost anyone can do it. The average user (unlike us) doesn't know how to implement RAID or JBOD in a mainboard BIOS; they just want a box they can slap another drive in, regardless of size, and it works. Most users also aren't going to build a WHS box; they'll buy one. Acer, Lenovo, and HP all make them.

    At first, I would have rather had RAID when WHS was in beta. Now that I've had a WHS box, I'd much rather have Drive Extender.
  • Photon0000 - Monday, December 20, 2010 - link

    Without Drive Extender with a feature set like in DE v1 Windows home server will simply disappear. I work in IT and THE key reason I bought WHS is DE. Something as close to an appliance as possible is what I need at home where Data protection maintenance free and anybody can do it in a few moments work is important. The ability to remove a drive from the pool and put in a larger drive of any size to add storage made this the perfect solution for DVR, multimedia storage and streaming. The ability to remove a drive from the server and access what is on it by connecting it to another computer is also extremely desirable.

    Now that HP has discontinued Mediasmart servers and disbanded the WHS team the best solution for families who cannot build their own is gone putting another nail in the coffin of WHS.

    I'll hold on the WHS v1 as long as I can but lack of 64 bit restore CD will ultimately kill it as 32 bit drivers become harder to locate and eventually disappear.

    WHS v1 does what it is marketed to do and performs well enough for that purpose.

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