I'm the author of HashBackup. I'd advise against using Amazon Glacier for pretty much anything, because retrieval requires a lot of mental, financial, and procedural gymnastics (4-hour delays, spacing our retrievals to keep costs down, etc). I implemented it for HashBackup when it was first announced, it was a nightmare, and I deprecated it a year or two later because alternatives like Backblaze B2 are nearly as cheap and have none of the retrieval headaches.
When talking percentages, sure, Glacier is $4/TB and B2 is $5/TB, so Glacier is 20% cheaper. But if you have to actually retrieve your data, it will likely cost more than any savings you've accrued. If you take a look at the S3 pricing page and your head isn't swimming afterwards, you probably don't understand the complexity of it. For example, they have data "retrieval" fees that are sometimes per request, sometimes per GB, and sometimes free (they promote that of course). But there's still that pesky 9 cents/GB data transfer fee that's on top of the per-GB retrieval fee, putting you at 10 cents/GB to retrieve data. Glacier also needs special tools: S3 tools can't access data stored in Glacier.
If you really want to stick with Amazon, I'd suggest S3 One-Zone Infrequent Access. It's a little more expensive, but you can use standard S3 tools to get your data back. You'll still have that 9 cents/GB retrieval cost, vs 1 cent/GB for B2.
When talking percentages, sure, Glacier is $4/TB and B2 is $5/TB, so Glacier is 20% cheaper. But if you have to actually retrieve your data, it will likely cost more than any savings you've accrued. If you take a look at the S3 pricing page and your head isn't swimming afterwards, you probably don't understand the complexity of it. For example, they have data "retrieval" fees that are sometimes per request, sometimes per GB, and sometimes free (they promote that of course). But there's still that pesky 9 cents/GB data transfer fee that's on top of the per-GB retrieval fee, putting you at 10 cents/GB to retrieve data. Glacier also needs special tools: S3 tools can't access data stored in Glacier.
If you really want to stick with Amazon, I'd suggest S3 One-Zone Infrequent Access. It's a little more expensive, but you can use standard S3 tools to get your data back. You'll still have that 9 cents/GB retrieval cost, vs 1 cent/GB for B2.