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Server 2012 R2 Certification – How to set up Deduplication – powershell commands


Server 2012 introduced “Data deduplication”, which scans for and removes duplicated files.  It saves on disk space.

1. Chunk Store

Date dedups relies on a “chunk store”, which is between 32 and 128kb… the average being 64kb.  Each chunk is stored in a container of around 1GB, before a new container is created.

2. Zero impact on users – each hour

Deduping has been designed to have zero impact on users.  It will check every hour for files that can be deduped.

It looks for files that are older than 3 days.

It works only on NTFS voumes.

You cannot dedup a Boot or system disk or SQL databases.

3. Turned off by default.

Oddly the dedup is turned off by default.  The powershell commands to turn it on are:

Add-WindowsFeature FS-Data-Deduplication

or if you want the GUI to set it up….

4. GUI Access via Server Manager

Server Manager > files and storage services > volumes

Right click the volume > configure data deduplication

Data Dedup Drop Down Box > General purpose file server

You may need to exclude certain files, folders or drives – such as the Active Directory Database called ntds.dit or a SQL database.

**Exclude file extensions – dit


Set Deduplication Schedule

Default = background dedup

Throughput is around 2 TB per 24 hours

Go to server manager and the dedup rate with show as a percentage %.



The Certification will test you on Powershell commands.

Powershell Commands for Dedup


Want to enable dedup on a particular drive?

Enable-DedupVolume E:\

Want to see how much disk space it’s saved us?



Want to kick off a manual dedup to speed things up?

Start-DedupJob -Type Optimization -Volume E:

Start-DedupJob -Type GarbageCollection -Volume E:


Want to see how far the dedup has got?




Want to see the statistics of the dedup?

PS E:\>Get-DedupMetaData






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