Tech Blog

How to disable Dedup:

First an important point about disabling dedup (via GUI or PowerShell), when you disable it only stops further deduplication from occurring i.e data that has already been deduplicated will remain deduplicated

If you want to “move” the data back to the original files and out of the deduplication store (Chunk Store) you need to use powershell command

start-dedupjob -Volume <VolumeLetter> -Type Unoptimization

You can check the status on where this is at by using

get-dedupjob

Here’s another gotcha, chunk size (love that name) will not get smaller until you run two more commands, GarbageCollection and Scrubbing.  GargabeCollection will find and remove unreferenced chunks and scrubbing will perform an integrity check but this wont work unless dedup is on….so enable dedup:

Enable-DedupVolume -Volume <VolumeLetter>

Then run garage collection:

start-dedupjob -Volume <VolumeLetter> -Type GarbageCollection

start-dedupjob -Volume <VolumeLetter> –Type Scrubbin

Once your drive is small again then disable dedup:

Disable-DedupVolume -Volume <VolumeLetter>

Found a drive was running low on space today and on closer inspection with tree size I found that ChunkStore (brilliant name) was taking up the drive space:

Odd as it looks as dedup wasn’t working:

To fix it I ran the following PowerShell:

start-dedupjob -Volume <VolumeLetter> -Type GarbageCollection

start-dedupjob -Volume <VolumeLetter> -Type DataScrubbing

What does this do I hear you say, Garbage collection is the process to remove “data chunks” that are no longer referenced i.e. to remove references to deleted files and folders. This process deleted content to free up additional space. Data scrubbing checks integrity and validate the checksum data.

To monitor it I ran:

 Get-DedupJob

This seems to have fixed it for me: