Note: This article was originally published in 2019. Some steps, commands, or software versions may have changed. Check the current Data Deduplication documentation for the latest information.
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:
Get-DedupMetadata
Returns metadata for volumes that have data deduplication metadata.
Get-DedupMetadata
<String[]>]
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Full reference: https://docs.microsoft.com/en-us/powershell/module/deduplication/get-dedupmetadata?view=win10-ps
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.
Summary
You’ve successfully learned work with the data deduplication commandlets for powershell. If you run into any issues, double-check the prerequisites and ensure your Data Deduplication environment is properly configured.