Windows Server 2012: deduplication. and doal boot
This sounds as if deduplication is a bad thing. Well, it's a very neat feature of Server 2012. But you need to know what the consequences might be when you use this on your precious data. Does Windows 7 support dedup? Does Windows 8 support dedup? Let me tell you a little story about my experiences.
My demo environment @home consists of one server which is a dual boot. I had a Server 2008r2 / Windows 7 combo. This server has a RAID 10 with 3 partitions: the first one for my server C drive, the second one for Windows 7's C drive and a third for all my data and user profiles.
As you can see it was a bit outdated, so I decided to replace 2008r2 with the new Server 2012 Datacenter. (I've got a Technet account;-). After I installed and configured the new server, I wanted to try deduplication on mij data drive. The next day dedup really made my day! I had a whole 200MB extra free space on my data drive! Okay, so far so good. But, the server didn't like my little outdated videocard and I also had trouble getting Adobe Flash Player to work (it crashed constantly). So I decided to replace Server 2012 with Windows 8. I need the HyperV role for all my virtual servers and demo's, but since Windows 8 also has (limited) HyperV capabilities, it felt like a fine choice.
To install Windows 8, I needed a Win8 DVD. So I switched to the dualboot Windows 7 edition. I had to burn a Windows 8 ISO to dvd and the ISO was on my data drive (my deduped drive, right?). But when I tried to use that ISO an error came up stating that it wasn't possible to use this file... OOPS!!! Actually, I wasn't able to access ANY file on my data drive! Okay, good to know that Windows 7 does not like deduped disks.
Back in my dual boot Server 2012, I copied the Windows 7 ISO to another volume and rebooted into windows 7 and burned the DVD.
Windows 8 installed and after some config time I needed to start a tool that was on the data drive (yes, the one that got deduped). I got the same error as Windows 7 gave me! I wasn't able to open ANY file!!! Not even a simple photo of my daughter en me. HMMM....
Luckily there are some good folks on the internet who found out how to enable the dedup option in Windows 8. This is the site that I used: http://forums.mydigitallife.info/threads/34417-Data-deduplication-for-Windows-8-x64
After I downloaded the files and executed the 2 dism commands, I tried to access my data drive again. My heart was pounding in my throat. The first file I tried to open was that picture of me and my daughter. You cannot imagine how glad I was to see her face on my monitor again!!!
So, what have we learned here? Well, it's Server 2012 and Server 2012 ONLY that can access a deduplicated drive out-of-the-box. So, watch out what you're going to do with your external USB/eSATA drives, if you want them to be accessible by other OS's then Server 2012 also. Okay, lesson 2 is that we are able to add the dedup feature to Windows 8. But it's not handy when you have all your repair tools on your USB drive and when you want to help someone out with his or her pc, it needs a dedup installation first!
One final thought. There are some considerations when you want to use deduplication. For instance, don't use dedup on volumes that contain live VM's or SQL DB's. More about this can be found here: http://blogs.technet.com/b/filecab/archive/2012/05/21/introduction-to-data-deduplication-in-windows-server-2012.aspx
My server is a demo HyperV machine. I deduped my data drive which contains all my VM's. To avoid data corruption during scheduled deduplication while running live VM's, I've turned scheduled deduplication OFF and only manually start dedup when I know that all VM's are off.
