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Comment by cm2187 | Hacker News Reader

Perhaps a naive question but why would glacier try to discourage bulk retrieval? Is it because the data is fragmented physically?

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We don't actually know how glacier data is stored (though there are several theories from regular s3 to tape robots to experimental optical media).

I suppose part of the neat trick of it is that because we don't have to know, Amazon can switch it out for something else anytime it's convenient for them, or some new tech comes up. Or split thing up among several methods and compare costs. As long as they structure their operations such that nothing is ever lost and everything can be retrieved with a few hours notice at any time, they can try anything they want.

How would us knowing prevent them from doing this?

Whatever information became public, people would write scripts and the like with those assumptions baked in. Even if it wasn't officially documented, it'd be bad PR for Amazon to break things people were relying on.

I'm sure that was a commercial decision, not a technical one.

They could be running Glacier storage at cost (or even a slight loss).

But they make their profit when you try to get your data out.

I'm not implying anything nefarious - more along the lines that Amazon (could have!) looked at the market and compared demand to what they were offering. Then found something that scratched an itch...

In most of these cases, the technical decisions impact the commercial. If writing megabytes were "technically" cheaper than reading, you can either choose to pass that cost onto customers or simplify the pricing model assuming some read-to-write ratio.

They didn't just set the prices (or the pricing model) to amuse themselves.

Disclaimer: I work on Compute Engine.

Because they power down cold racks. It's called Glacier for a reason.

So they have to power them back up. But why would they care whether you then download 1gb or 1tb?

Because that's how they getcha. :-)

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