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When Bad Things Happen to Good Technology: RIP, Drive Extender

In this age of ten-second attention spans, bloggers are often guilty of over-dramatizing non-events to make them seem more important.

This is not such a time.

Microsoft today announced that it is removing its Drive Extender technology from Windows Home Server "Vail" (WHS v2) and Small Business Server 2011 Essentials (formerly "Aurora"). I mentioned this in today's daily update, and discussed it on Windows Weekly today, but based on the number of emails I've gotten, few people were aware that I had already discussed this topic elsewhere.

That said, I have some additional information that Microsoft didn't discuss in either of their blog posts (here and here) today announcing this decision.

First, let's review what Drive Extender was, and what it was going to become.

Drive Extender debuted in the first version of Windows Home Server in 2007. It supplies two key benefits: Data redundancy and a single, expandable pool of storage that doesn't require drive letters and is easily expandable.

The data redundancy feature is easy enough to explain: Through a simple UI in the WHS console, you can ensure that all of the files in a given share were duplicated across two physical hard disks. This ensures that, should a drive fail, your only copy of an important photo, document, or other file doesn't go with it.

The second one is like RAID for Dummies: It lets you add hard drives to your server and have their storage added to the WHS storage pool. You don't have to deal with drive letters, and because content is essentially stored in shares, the available storage available to those shares is limitless (or at least only limited to your server's ability to add more disks).

Drive Extender is awesome, and as the underlying technology responsible for two of WHS' best features, Microsoft was planning to expand its use beyond WHS, first to Small Business Server (in "Aurora") and then later to other versions of Windows Server and the Windows client.

So here's where we get to the bit that Microsoft didn't communicate for some reason: Why Drive Extender is being killed.

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."

Microsoft had tried to fix these problems, of course, and anyone who's familiar with WHS and tested Vail or Aurora will know that these products introduced a weird multiple-drive-letter scheme, tied to the shares, that was part of Microsoft's attempted fix. In fact, I found this "feature" so confusing, I went back to Microsoft with three separate sets of questions about it at the time.

So the question remains, of course, now what?

For SBS, the answer isn't all that painful: There is already a well established ecosystem of SBS partners that support Microsoft technologies, and the expectation is that hardware makers will bundle their own data duplication technologies with their products.

For WHS, the answer isn't great. WHS is a niche product--beloved, yes, but by a very tiny number of people--and is less well served by partners. Too, data products are expensive, and one of the best things about WHS wasn't that it had Drive Extender per se, but that it had this huge collection of useful features, some of which were DE-related.

Microsoft says it will deliver a new Vail beta in January, and at that time we can see what a DE-less WHS version looks like and start thinking about what we're going to do going forward. My home "infrastructure" is currently on the Vail beta refresh/release candidate/whatever that was, and it's working well. But clearly, that's a temporary situation, and I'll have to figure that out. Whether that something is still Vail, or some combo of Vail and Drobo, or some future NAS, or whatever ... I don't know. I may have known about this longer than some, but I'm as confused as anyone.

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