The use of AWS S3 storage to store SQL Server backups makes sense, firstly it is significantly cheaper than EBS, secondly you can encrypt what’s stored and thirdly you can manage backup file retention and lifecycle using inbuilt functionality.
Consider the following situation, you create a database backup on a AWS virtual machine EBS disk and then move the backup file to Blob storage e.g. S3. However, you have switch on the Encryption option for your S3 storage. Is your database backup file fully protected? Yes, well, sort of.
Following on from my backup performance post, the next challenge was trying to restore a backup on the mirrored server within a reasonable time. In this case, a reasonable time was 3 to 4 hours as opposed to 12+ hours. Again the issue we faced on AWS was the 39 MB/sec throughput limit per high