Technical Failures Emerge as Reason for Death of Drive Extender

by Alex Kuretz on November 24, 2010 · 15 comments

in News

Paul Thurrott has a blog post that explains technological problems as the real reason that Microsoft is removing Drive Extender from Windows Home Server. In briefings earlier in the month, Paul had a discussion with Kevin Kean, the general manager of the (Home and) Small Business Server team at Microsoft, who had this to say.

In a briefing last month, I was told that Microsoft and its partners discovered problems with Drive Extender once they began typical server loads (i.e. server applications) on the system. This came about because Drive Extender was being moved from a simple system, WHS, to a more complex, server-like OS (SBS “Aurora”) that would in fact be used to run true server applications. And these applications were causing problems.

“Drive Extender was a neat feature, but the implementation was off, and we discovered some application compatibility and disk tool problems related to its ability to correct data errors on the fly,” Microsoft general manager Kevin Kean told me. “We don’t want to give customers problems; we want to give them solutions. So ultimately, we decided that we needed to cut out Drive Extender. Removing Drive Extender will make file shares easy, and it’s possible to accomplish most of its features otherwise. For example, you use the server’s centralized backup or even RAID as an alternative to data duplication.”

This explanation is much more understandable than the vague, nonsensical ramblings of yesterdays blog posts from the (Home and) Small Business Server team, who attributed the removal of Drive Extender to customer requests and the prevalence of large capacity hard drives.

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I'm Alex Kuretz, and I'm the founder of I was the Lead Test and Integration Engineer at HP for the MediaSmart Server until April 2008 when I moved on to other opportunities outside HP. I've kept active in the Windows Home Server community, creating several add-ins and helping users make the most of their Home Servers.


Seth November 24, 2010 at 9:01 am

So…just leave it in the home version and go with RAID or whatever for the business versions. They’re throwing out the baby with the bath water.

alanh November 24, 2010 at 9:02 am

If it wasn’t for Drive Extender, I would not have purchased a WHS (HP ex490) at all. I was very much looking forward to extender v2 as it would have greatly improved on the duplication speed for large files. This is an incredible disappointment to me.

Paavo November 24, 2010 at 10:00 am

I’m not happy with this explanation. WHS is not supposed to run “server applications” or “disk tools”. SBS/Aurora is, but WHS is not. So what gives MS? You are removing DE because users may run into problems when running applications that are NOT even supposed to be run with WHS?

Oh dear. I have to repeat what Seth just said: “They’re throwing out the baby with the bath water.”

Awake November 24, 2010 at 10:05 am

The explanation is a crock of you-know-what when it comes to WHS, since by design and support policies, WHS has always been a ‘run applications at your own risk’ platform. So that explanation is no better than the “our customers talked to us ” excuse given yesterday.

So now we end up with a less functional version in Vail than we did in Version 1, and NO added features. None. Nada. Server 2008 adds NOTHING to the functionality of WHS.

If we are going to be honest and realistic, the data duplication and drive expansion capabilities of WHS should be part of a basic OS such as Windows 7, making it easy for users to add reliability and expandability to their desktop systems. Instead, the ONLY product offered by Microsoft to help home users is now crippled beyond basic functionality.

Microsoft is showing a level of incompetence rarely seen in companies of it’s maturity. They break perfectly fine technology. 4 years late they come up with a phone with V1 features compared to the competition. Tablets have been a non-starter for them.

It is a consequence of companies growing too big and arrogant and forgetting about their customers. Adobe suffers from the same mental disease (people are starting to hate Photoshop). Companies like Microsoft ride cash cows like Windows and Office, but that will only take them so far. And now they alienate their core fans and supporters.

BTW, I refuse to use Apple products… they are the kings of “F%$ you if you don’t like it”. I will still use Windows as my desktop OS, but for everything else (media centers, tablets, phones, storage, even documentation) they are far from my first choice.

EricE November 24, 2010 at 8:29 pm

I see this as much ado about nothing. DE is irrelevant vs. simple disk mirroring for two simple reasons: Hard drive capacity and price per gigabyte. For less than $400 I can have four useable terabytes of fully protected storage. Storage that is protected 100% of the time, and not just when the file is closed and a duplication task gets around to syncing it to another disk. Protection that isn’t flaky if I have large files or a server under constant load (try six IP cameras recording – hello!)

Quite simply, I can have two mirror sets of 2TB drives (or two mirror sets of 3TB drives for 6 useable TB, but 3TB drives are at a premium due to their newness) for less than what it would take to mix and match drives under DE when WHS was first released.

When WHS was first released, DE was a pretty neat way to maximize your cost per gigabyte – but that goal is pretty much moot at this point, and I think that is what the WHS team was trying to communicate – albeit clumsily. When I can find a plethora of 2TB 3.5″ desktop drives for $80-$99 with less than a minutes googling, DE is now a solution for a problem that doesn’t exist.

DE under WHS v1 was a hack. A pretty elegant one, and one that works pretty well for most use cases (well, once they solved that one really nasty data corruption bug) – but quite frankly, I think MS (correctly) realized that DE really isn’t needed for the true WHS target market in the long haul. One only has to look at the lengths they were going through to try to ensure data reliability with Vail, and it quickly becomes obvious that in the context of todays hard drive capacities and pricing that the overhead and complexity of DE is no longer needed. Kudos to someone at MS for having the stones to call DE on it’s nakedness and pull the plug.

I imagine I am in the minority, but bravo to MS for dropping DE. It was a good compromise at the time, but it never was 100% reliable, and it didn’t offer any real space savings over mirroring. It did introduced a ton of complexity and uncertainty compared to simple mirroring, other than being able to mirror only part of a disks contents – whoopee. If you need non-redundant storage buy another drive for the stuff you don’t want duplicated – they are cheap! You don’t need DE to sub-allocate drives. Perpetuating DE these days would be the epitome of “penny wise, pound foolish”

I won’t miss DE. And if you need more than 6TB of redundant storage, I would say you aren’t, strictly speaking, a *Home* Server user. Vail and Aurora support iSCSI – grab a refurb Drobo Pro to attach to your WHS and have at it. As you load that Drobo up, it will be far more cost effective in the long run, offering you more usable storage for the size of the array/number of hard drives you have – the savings are pretty dramatic as you fill the array out. WHS is still compelling for it’s native Windows server SMB support and the excellent workstation backup (with bare metal restore and data de-dupe to boot!).

I think MS correctly realized the issue isn’t DE – it’s the core problems with RAID with parity and NTFS in storage flexibility. OEM’s partnering with Drobo, OEM’s working with MS to come up with better implementations of RAID with parity, MS Licensing ZFS from Oracle – who knows what waits in the wings. Hopefully there is something else or this will be a dud – even if it’s as simple as for Windows *home* server working with OEM’s to come up with easy ways to implement mirror sets for protected storage and single drives for un-protected storage. Frankly it’s something that’s overdue anyway – I never was overly confident in DE. Mirror set advantages over DE:

* Instant duplication of each block as it’s written

* No open file conflicts

* No unprotected data until some background duplication task runs

* Retains the ability to pull a drive, plug it into another computer and pull your files

* No load issues, limitations with large files

* No weird NTFS/file share hacks required – Hello, DFS anyone?

Granted, RAID with parity is still a bag of hurt (except for Drobo) – but DE didn’t address that anyway so I don’t understand the “OMG WHS IS DEAD” sentiments. Talk about myopic over-reactions…

What MS could do is simplify Branch Cache in Auroa (SBS Essentials) so small business with more than one location, or an owner who wants to take an Aurora box home can implement in-house off site backups for redundancy. Booyah! Heck there are probably plenty of current WHS users who wouldn’t mind dropping a WHS box at a relative’s house for private remote, off site backup with no monthly fee. Hmm – I may have to unearth my Vail beta VM and see if you can activate branch cache – then again, with DE gone that will be much easier now!

Things that make you go hmmm…..

wildbilll November 25, 2010 at 10:20 am

I agree that the DE feature elimination is a tempest in a teapot.
I am seeing 1TB drives advertised for $50 this weekend at Microcenter.
Adding additional capacity isn’t difficult for me and I think a wizard that helps the typical home user add a new drive to storage, assuming the next beta will look more like windows 7 in the regard, will take away the pain.
Another aspect of this is that PC users know and understand the file systems of Windows PC’s. This change should make them more comfortable with WHS v2.
I know this isn’t a deal breaker for me or the OEM’s that sell them.
The backup feature is why I bought a WHS machine. The webserver is nice, so is the Remote desktop access to my PC’s.
The media serve/conversion is OK, but I don’t care if stays or goes.
The bulk of the users want reliable backups and if DE is flaky, then I say good riddance.

Matt Sawyer November 24, 2010 at 9:06 pm

Please visit the FB page I created, WHS Users in Support of Drive Extender, and “like” it. There is strength in numbers, and hopefully we can convince Microsoft that they’re making a HUGE mistake!!/pages/WHS-Users-in-Support-of-Drive-Extender/143773099008485

Matt Sawyer November 24, 2010 at 9:07 pm

The failures cited are with DEv2, which moved DE’s implementation from above to below the file system. That’s a huge architectural change.

If DE isn’t holding its own in the heavy-hitting business world, take it out of the business products. If DE is still having trouble, then throw out DEv2 and go back to DEv1. DEv1 worked, and it worked well. It wasn’t broke, so there’s no need to fix it!

That might delay Vail’s release several more months, but it will be worth it!

EricE November 24, 2010 at 9:26 pm

“DEv1 worked, and it worked well. It wasn’t broke, so there’s no need to fix it!”

Actually DE doesn’t work well with larger disks, larger files, or servers under load. Heck, with a lightly loaded WHS and the Tivo add-in from HP, I get file conflicts all the time. Blame it on HP or whatever you want, but the fact is with drive mirroring it wouldn’t be an issue. Period.

If you have been following the progress of the Vail team in trying to address the weaknesses in the original drive extender technology, it’s pretty obvious why they decided to drop DE.

DE made sense when drives were far more expensive and far smaller, but no longer.

Seth November 25, 2010 at 10:51 am

“Actually DE doesn’t work well with larger disks, larger files, or servers under load. Heck, with a lightly loaded WHS and the Tivo add-in from HP, I get file conflicts all the time. Blame it on HP or whatever you want, but the fact is with drive mirroring it wouldn’t be an issue. Period.”

That’s an interesting claim to make on a website used by a fairly good sized contingent of WHS users with 10TB+ drive pools containing HD movie files in excess of several gigabytes. In my case alone I’m currently at 12TB (which is impossible to do with a single mirrored array using existing drives) and have multiple BluRay files exceeding 20G. I meet your definition of larger disks, larger files and “under load” and the only time I’ve ever seen file conflicts is when running DriveBalancer (which go away after DriveBalancer completes its run) and the same goes for numerous other WHS users I know so you shouldn’t be so quick to blame DE.

I’ve got plenty of experience with RAID arrays of all types, both software- and hardware-based. For ease of implementation, ease of use and ability to upgrade drives I’ll take DE over any of them (although I’m getting interested in unRAID simply because of the similarities it has to DE). If MS doesn’t put DE back into the “consumer” version of WHS v2 they’re going to find out just how many people think they’re wrong from all the upgrades that end up not taking place, myself included.

EricE November 29, 2010 at 2:49 pm

“they’re going to find out just how many people think they’re wrong from all the upgrades that end up not taking place, myself included.”

Hardly a threat – for all the benefits of WHS it wasn’t exactly a barn burner (which is a shame, I’ve become a real fan of it).

People such as yourself are a minority in a product that is an extreme minority of the market share.

I still think it’s premature to assume that there won’t be some sort of a functionality replacement from either MS or the OEM vendors. Personally I was looking forward to hookup up a Drobo to Vail and bypassing DE altogether. For those it’s working fine for – great. But it’s far from bullet proof or consumer friendly when there are issues, and I think that’s what MS was attempting to come to grips with with V2.

Comp1962 November 25, 2010 at 3:32 pm

Its a wait and see thing. There is arguements to be made for both sides as is always the case. What more important to me here is that it be simple for Consumer Grade Servers. In the end if its simple, and the redundancy is simple and take into account the use of consumer grade hard drives then lets see what MS does come out with.

I just want simplicity and regardless of what opinions one may have for DE and all its quirks it does work and while it may not be the most efficient thing out there it works and whatever they replace it with I certainly hope it works in such a way that the average consumer can just pop in drives of their choice and have it work.

I do not care so much about the Business end of things or the efficiencies and demands that they require. I am more concerned with the Consumer end of things and do not wish nor desire to have a system that might be the best in the world but require a certification to understand, run and maintain it.

WHS v1 is simple, easy to use and enjoyed and relied on by many. While not perfect it works, its simple and does not require a wealth of knowledge to keep it running. MS needs to keep this in mind for the Consumer Grade Servers or just opt out of the Consumer end all together.

If we go back a few years the consumers myself included who wanted a centalized storage system and a location for backups used and relied upon the NAS and it was far from perfect. WHS also far from perfect offered something the NAS did not, simplicity, easier to use, and for client backups a bullet proof system that has yet to fail me something a NAS solution was never quite able to do with the efficiency of WHS.

So lets wait and see and maybe MS will find a way to make WHS v2 simple for the Consumer and its all I can ask for. If not then I am quite happy to stay with WHS v1.

element November 26, 2010 at 1:12 pm

windows HOME server isn’t designed to run server-applications, so therefor it shouldn’t be a problem. As it’s been mentioned before, this is just MS going for the big money in the low number of business sales rather than the small money in the large number of home sales

varun November 26, 2010 at 6:21 pm

This seems like a no freaking brainer: port the Quattro version of DE (V1) which had DE above the NTFS layer into Vail and be done with it. Stop wasting time on the V2, which offers reduced performance for what is basically an issue solved by middleware – BDBB.

Patrick J. Greene November 27, 2010 at 8:53 am

This makes sense. They don’t give a flying f#$k about the consumer, this v2 is geared to the SOHO market, so toss out DE with the consumer. Makes sense.

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