I don't know about cost, but I've used "sneakernet" several times because the performance is better. If I had 100Gib on Internet2, that would evaporate, but I'm in the US, and my company has a T1, so transferring even a few hundred GB takes a while. A T1 delivers:
~11.5 MiB/m or
So it takes a couple months to upload 1TB, whereas with Sneakernet you put it on a hard drive, and ship it in a day or two. So this make a lot of sense for US companies dealing with large datasets--unless you're one of the select few with a true next-generation connection, sneakernet is faster.
Whether it's cheaper is less clear, but it looks like it's at least competitive. The numbers that are being thrown around, like 100Mib/s for US$45, are probably:
- Consumer prices (not available to companies).
- Restricted by terms-of-use agreements, preventing this sort of wild and sustained bandwidth usage.
- Download speeds, with vastly slower upload speeds. It doesn't help if you can download at 100Mib/s, if the sender can only upload at 1Mib/s.
I'm speculating on all these, and please clarify if these aren't the case, but that's how it works in the US. You can get a good price on a pretty fast download pipe (in the US, that would be 5Mib/s), but the upload speed will be much slower (often under 1Mib/s), and they will cancel your account if you do anything like full utilization. They're not intending to let you use 100Mib/s sustained; they couldn't possibly afford it at that price. They're thinking you'll a few kib/s sustained (average), with bursts of 100Mib/s, so they can cram you and 100 neighbors into the same 100Mib/s slot. To really see what bandwidth costs, you cannot look at consumer prices, you have to see what they charge businesses for connections that can be fully loaded (they'll still double those up, but not nearly as much).
When I first read about the big telescopes doing this, and wondered why they didn't use the Internet, my collegue and I ran the numbers and realized how much faster it was to ship tapes. Our conclusion: great bandwidth, but lousy latency!
Several people asked what happens if the package is lost or destroyed in transit. Well, what if the packet is lost in transit? TCP re-sends it. In sneakernet, you are playing the part of TCP, so if it's lost or destroyed, you hear that from the recipient, and you send another one. Packets are rather expensive in sneakernet, but if your network is of a quality that few packets are lost, the average cost to re-send one won't be high. There's a cost in time too, just like TCP, but where TCP can resend the packet in a few ms, it will take you a day or more. If you want to reduce the change of a catastrophic loss, follow TCP's example and use smaller packets; send it on individual 100GB hard drives, in separate shipments, and resent only those that don't arrive intact.
Great bandwidth, lousy latency!