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I'm using Glacier app on my QNAP NAS drive and was backing up some folder and I'm wondering if Glacier is using any file compression? Folder original size is 41.5GB and on the Glacier Management Console I see this container/vault have 36.5GB - is that correct and it's a compression or my NAS just didn't backed up everything - how I can verify files integrity?

The questions is about Amazon Glacier - not the NAS drive - however I don't know how the app works - and if compression is not implemented in the app itself, I just want to know if glacier itself is compressing on-the-fly data or not?

I couldn't google this info anywhere.

Many thanks, Peter.

John Rotenstein
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snoopy
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1 Answers1

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Glacier doesn't compress data.

There are two different definitions of "gigabyte" -- one binary (1024 x 1024 x 1024, properly called "gibibytes" and abbreviated GiB, though sometimes casually called "gigabytes" and abbreviated GB) and one based on metric prefixes (1000 x 1000 x 1000, this one is properly called "gigabytes" and abbreviated GB).

I don't think that explains the discrepancy, here, since 41.5 gigabytes = 38.65 gibibytes. Closer, but probably not close enough.

Googling found some qnap documentation that suggests qnap itself supports compression and sparse file detection, either of which might have reduced the size of your backup, and that qnap saved each file as its own archive within a vault, which should give you something to go on, as far as trying to validate the backup.

Michael - sqlbot
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