We are using Amanda to send backups to S3. Each host is acting as its own Amanda "server".
All hosts are currently using the same S3-bucket -- each has its own subfolder under it. The dumps are saved with "
REDUCED_REDUNDANCY" -- it is 20% cheaper and we consider it unlikely, that both the original host and the backups will disappear at once.
We do not currently specify, where the bucket is stored -- using whatever Amazon does by default.
Our EC2 systems are spread across different regions, however, and we are wondering, if, perhaps, we should use multiple buckets -- one explicitly created in each region storing dumps of hosts from another region. For example, make us-west-1 hosts send their dumps to the us-west-2 bucket (or even to us-east-1) -- to keep the backups available should Amazon lose a particular region entirely (both the EC2 virtual machines and S3 data).
Would that be useful, or is S3-data already mirrored to multiple regions by default? Will there be increased billing costs -- it is our understanding, that writing to S3 is free, and storage costs the same -- is that correct? Latency is of no particular concern -- as long as bandwidth remains decent.