That's what I thought as well, but recently found out otherwise. While it is true that, for buckets in the US Standard region, requests are routed to the closest endpoint, the data still only lives in one location.
To clarify by way of an example, say you're putting data into S3 from an EC2 instance in us-east-1. Those requests will end up being handled by the NVA US Standard S3 endpoint, and the data will only be stored in NVA. If try and retrieve that key from an EC2 instance in us-west-2, that request will indeed be routed to the PNW S3 endpoint, which will see that it doesn't have a local copy of the object and will need to retrieve it from NVA before serving it to you. That object will be cached locally in the PNW endpoint for an unknown amount of time, after which it will need to be retrieved from NVA again.
All of this information was from a recent support ticket I had open with AWS while trying to troubleshoot poor S3 performance.
The verbage they use to describe the US Standard region is quite confusing, leading a lot of people to assume that it provides geographic redundancy when it actually does not provide this at all.
To clarify by way of an example, say you're putting data into S3 from an EC2 instance in us-east-1. Those requests will end up being handled by the NVA US Standard S3 endpoint, and the data will only be stored in NVA. If try and retrieve that key from an EC2 instance in us-west-2, that request will indeed be routed to the PNW S3 endpoint, which will see that it doesn't have a local copy of the object and will need to retrieve it from NVA before serving it to you. That object will be cached locally in the PNW endpoint for an unknown amount of time, after which it will need to be retrieved from NVA again.
All of this information was from a recent support ticket I had open with AWS while trying to troubleshoot poor S3 performance.
The verbage they use to describe the US Standard region is quite confusing, leading a lot of people to assume that it provides geographic redundancy when it actually does not provide this at all.