I have created a secondary AWS account for the backup script to use. I have given this account write access the the backup buckets in S3.
Backup worked properly when I was using the access keys for the 'owner' account. But with the secondary account (which has read/write access), backup failes with the message:
Failed to create S3 bucket : The requested bucket name is not available. The bucket namespace is shared by all users of the system. Please select a different name and try again.
Backup failed! See the progress output above for the reason why.
It looks to me like Virtualmin is trying to create the bucket because a bucket of that name does not belong to the AWS account it is logging in as. This is a mistake because the bucket does exist and the account has read/write access to it. However, I have not looked at the source code (my Perl skills are a little rusty!)
I am running Virtualmin version '3.64 Pro'.