Decompressing NTFS files

I recently had to do a Veeam restore of a Hyper-V server. The restore went well although the Veeam deduplication add quite a bit of time to the restore processes because it has to “reduplicate” what it “deduplicated”.

The bigger issue was the fact that the VHDX file that was restored was COMPRESSED, as in the context of NTFS compression.

NTFS compression is something that I have stayed away from. There is simply little need for compression in the age where disk storage is so incredibly cheap. But Veeam restores the files as compressed.

Hyper-V will not mount and run compressed files, so they have to be uncompressed first. In this case, the VDHX file was big – 150 GB – and we weren’t sure how long it would take. Worse, unchecking “compress this…” and clicking OK gives no progress indicator at all.

But, if you simply right click on the file, go to Properties, you can see the uncompressed (size) and compressed (size on disk) file sizes. Hit cancell, wait a bit, and you can go back in and see what difference there is between the two. Taken over a period of time, this can give you a good idea of how long the decompression is going to take.

Note РIn this case, decompressing a 150 GB  file took about seven hours.

NTFS uncompression times decompression

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