Windows Server 8: Massive storage enhancements ahead

Microsoft makes big investments in data deduplication, live disk repair and more...

In the first part of my 2-part review of Windows Server 8 I looked at some of the best of the more than 300 new features Microsoft packed into the upcoming server OS. Now it's time to turn our attention to some massive storage enhancements.

[ See also: Windows Server 8: Highlights of the upcoming server OS ]

Data deduplication

My personal highlight of the entire three days of the Windows Server 8 reviewers workshop were the talks about Storage. The killer-feature to me is the new and built-in data deduplication, which detects duplicate data in files and folders, puts it in a separate store (System Volume Information) and simply gets rid of the redundant bytes. The file itself is 100% intact, though once it gets accessed it pulls the (now missing) information back from the one single data store.

Now, deduplication isn’t something groundbreaking. It's been done before, and it's been done well, but dedup has never found its way into the OS, which means it's deeply integrated and highly manageable. Microsoft Research invested 2 years on this algorithm and came up with techniques to minimize the performance impact caused by pulling one piece of data from one part of the disk and when fetching other pars from the data duplication store (fragmentation!); according to Microsoft's server team, dedup has a less than 3-4% impact on overall performance when accessing the data, although only performance tests will tell the true story.

However, the benefit greatly outweighs the possible downsides. Generally, you can expect a chunking rate of between 30% and 90%, which is absolutely amazing. On day 3 of the Windows Server 8 reviewers workshop, I had the chance to catch up with the development and program management team behind data deduplication and found out a couple of interesting tidbits:

  • Deduplication automatically runs on "idle". Say you've enabled deduplication on drive E and copy 20 gigs of files over, deduplication wouldn't start immediatelly. It would, however, wait until the server isn't quite as busy and perform the deduplication process. You have to keep in mind that going through files and detecting data is quite an I/O eater.

  • Admins can determine which files get deduplicated based on their age. Maybe you don’t want to dedup files that the server just created.

  • Failsafe: When asked about the possible risk of having one important part of possibly dozens or hundreds of files in one chunk, I was told that several failsafe mechanisms are in place that perform file system health checks on the specific area that the deduplicated data gets written to. Also, if your server accesses data very frequently (they wouldn’t share a number), it gets automatically duplicated again to avoid possible risk.

And, by the way, this very same technique applies to network transfers (think VDI!) and even local RAM. Windows Server 8 saves local memory by finding duplicate information and getting rid of it.

ChckDsk Ultimate: Live disk fixing

After decades of putting up with Chkdsk, which essentially takes your servers offline for hours in case of a hard drive disaster or crash, Microsoft came up with a major revamp of the infamous disk checker tool. ChkDsk offers (finally!) an online scan and corruption logging mechanism. It marks defective clusters and files during runtime and cleans them later using a technique called "Spot Repair," which shows itself both through the UI (Server Manager, Action Center) and PowerShell.


The "Spot Verifier Service," which is part of the Windows 8 client as well, attempts to repair disk issues on-the-fly. If that's not possible, maybe due to a more critical file system error, admins have the chance to attempt and perform an instant repair using the the "spotfix" parameter or schedule a chkdsk for later.

If possible, chkdsk simply eliminates the errors that the "Online scan" feature logged, which takes only a few seconds or minutes compared to the hours that you'd have to wait on Windows Server 2008 R2.

Network performance and reliability

Being a server OS, Microsoft invested quite heavily in speeding up network performance and robustness. D-VMQ (Dynamic Virtual Machine Queue) helps avoid CPU bottlenecks in high-bandwidth situations by effectively alligning the network traffic to processor cores -- you'll end up using only a fraction of the original CPU performance under high bandwidth usage. Second, the overall priorization of traffic has been improved, with the admin being in full charge of dynamically reserving bandwidth for particular traffic. Second, the new "NIC Teaming" feature allows you to combine adapters and essentially scale network performance with every NIC that gets added (e.g., get two 10 GB NICs and essential drive 20 GB down the lines). What's really interesting about this is the fact that you can combine NICs from different vendors (e.g. Broadcom or Intel).

In the reliability department, Windows Server 8's team has also done its homework: "DHCP Failover," which previously was left to 3rd party vendors and essentially left out of Windows Server 2008 R2. Now it's built right into Windows Server 8: it allows you to easily specify a secondary DHCP server, which immediatelly takes over on fails.

Remote FX: Big enhancements

Remotely logging on to a client over WAN (even LAN or via mobile broadband) had its drawbacks: lags, dropped video and slow file transfers. Remote FX has also been improved massively: Windows Server 8 automatically detects what type of content gets transferred over the remote connection and chooses the right codec (e.g. for text, images, videos -- h.264 is the key). RFX adapts to the current situation and reduces the bandwidth load drastically; depending on what type of content you're generally accessing remotely, you can expect a reduction of bandwidth of up to 90%.

Nice: Remote FX supports full multi-touch. You can use a local touchscreen and control a remote machine with nothing but your fingers. Another great addition that's likely to make admins happy is full USB passthrough.

Bottom line

Windows server hasn't had such a massive change in a long time (or, maybe, ever). Keep in mind though that at this point in time, it's still a developer preview. As is the case of the Windows 8 client, things aren't as smooth as they could be and it's likely that some of this stuff is even going to change. We'll keep you posted.

This article, "Windows Server 8: Massive storage enhancements ahead," was originally published at ITworld. For the latest IT news, analysis and how-tos, follow ITworld on Twitter and Facebook.

Sandro Villinger is a contributor to ITworld. For more by Sandro, see:

15 incredibly useful (and free) Microsoft tools for IT pros

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Hyper-V & virtual PCs: How to handle virtual disks.

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