[kevincox]

It would be fairly easy to change the pricing policy. GCP did something similar for cross-region https://cloud.google.com/storage/pricing-announce#network. This is pretty severe because it seems to affect all reads. However I can imagine an alternate implementation where the source AZ is tracked when data is written and egress fees are charged when the data is read (as if the data was always stored in the source AZ). This could even be done more complexly such as only charging the first time data is read in another AZ. Once you read once it is free as-if it is now cached in that new AZ forever. Another option would just be raising the minimum storage duration so that it basically costs all or most of what the data transfer would.

It would definitely piss a lot of people off as it is adding to their bill, but it could likely be done in a way that makes exploiting this for just data transfer not worth it without adding huge costs to most "real" use cases.

[danielklnstein]

Yeah, I see what you mean - that'd indeed render this method ineffective. Like you said I'm sure this would bother a lot of customers, but it's not a completely unrealistic overhaul of S3 pricing.

That being said, that'd be sort of "mean" of AWS to do - the data is already replicated across AZs whether you pay for it or not because of how S3 works.