Windows Server 2012 has a new feature called Data Deduplication which can be worth to try.
You can install this feature from Powershell as follows:
PS C:\> Import-Module ServerManager
PS C:\> Add-WindowsFeature -name FS-Data-Deduplication
PS C:\> Import-Module Deduplication
How Much Disk Space Can I Expect to Reclaim?
When you install the Data Deduplication role service on a server running Windows Server 2012, DDPEVAL.EXE is also installed in the C:\Windows\System32 folder as an additional command-line tool. DDPEVAL.EXE can be run against any local NTFS volumes or NTFS network shares to estimate the amount of disk space that can potentially be reclaimed by moving that data to a Windows Server 2012 NTFS volume with Data Deduplication enabled.
C:\> DDPEVAL \\server\folder /V /O:logfile.txt
When you find out if the space that can be reclaimed is substantial, you are ready for the next step, running Optimization Jobs:
In Windows Server 2012 Data Deduplication, Optimzation Jobs perform the work of deduplicating data and optimizing a volume. These jobs can be run on-demand (manually) or on a scheduled basis.
You can trigger an optimization job on-demand in Windows PowerShell by using the Start-DedupJob cmdlet. For example:
PS C:\> Start-DedupJob –Volume E: –Type Optimization
You can query the progress of the job on the volume by using the Get-DedupJob cmdlet:
PC C:\> Get-DedupJob
Source: Keith Mayer Blog