How to: Work with the data deduplication commandlets for Powershell

In a previous article I wrote about using Windows Server’s awesome feature of Data Deduplication. I love this feature as it allows you to save space as data is often duplicated in the datacenter. So… one of the main downsides of using ReFS (Microsoft’s newest file system for Windows Server) is that it didn’t support Data Deduplication… but with Windows Server 2019 now it does! So very excited to see that feature included finally after more than a 7 year wait. Anyway, as it became enabled I dived back into data deduplication and wanted to share the main commands I use and my lessons learned:


This one I like because I can finally see the details of the data deduplication savings. Here is an example:

PS C:\WINDOWS\system32> Get-DedupMetadata

Volume : N:
VolumeId : \\?\Volume{fb31d6cc-9805-4108-a57a-82147086b54d}\
StoreId : {00000000-0000-0000-0000-000000000000}
DataChunkCount : 0
DataContainerCount : 0
DataChunkAverageSize : 0 B
DataChunkMedianSize : 0 B
DataStoreUncompactedFreespace : 0 B
StreamMapChunkCount : 0
StreamMapContainerCount : 0
StreamMapAverageDataChunkCount :
StreamMapMedianDataChunkCount :
StreamMapMaxDataChunkCount :
HotspotChunkCount : 0
HotspotContainerCount : 0
HotspotMedianReferenceCount :
CorruptionLogEntryCount : 0
TotalChunkStoreSize : 0 B

As you can see, there is a throve of data available and that is what makes this such a powerful tool. 

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