Real world data deduplication savings under WIndows 2012
Though Microsoft provided a tool that gives a generic preview of the results a system administrator can expect from this new mechanism (the tool I am talking about is ddpeval.exe), I think that sharing real world statistics on a filetype basis can greatly help the understanding of its usefulness.
So I have decided to use a bunch of disks in a one-to-one relationship with one type of file and enable deduplication at filesystem level.
I had in my stock four 50 GB SATA disks which I formatted with NTFS (remember that Windows 2012 new ReFS doesn’t support Dedupe for the moment).
I run three series of tests.
In the first series of tests, I copied on each disk one single file and made enough copies of it to fill 10 gigabytes of space. The file extensions that I choose for this test are quite common files everyone has in his data: .avi for a movie file, .mp3 for a audio file, .doc for a Microsoft Word file and .iso for a disk image. These file extensions cover the types of files you find in media libraries, document libraries as well as software libraries and having an idea of what Windows 2012 deduplication can do for you is important.
On my first disk, named F:, I copied the .avi file whose size in 700 MB. I then made 15 copies of it in order to use 10 GB.
On the second disk, H:, I put the mp3 file whose size is 4.50 MB. I made 2291 copies of it in order to use 10GB.
On the third disk, L:, I stored a 1.75 MB large Microsoft Word document, then I made 5277 copies to take 10GB.
On the last disk, M:, I copied a pretty big 3.09 GB ISO image that I copied three times to take a little bit less than 10GB.
On these four disks I enabled Data Deduplication and waited for it to occur. A few days later I came back to see the results and they were as good as I expected, being those hundreds and thousands of files just replicas of the same original file and the probability of having identical blocks equal to 100%.
Ok, let’s make the number talk. Here’s the results I got:
Get-DedupStatus FreeSpace SavedSpace OptimizedFiles Volume