On 9 Sep 2019, at 07:47, James Brown <jlbrown@bordo.com.au> wrote:

Should I use a Dovecot process, rsync, a Mac app like Arq or Jungle Disk, or something else?

I do not have specific experience with using S3, but if rsync is possible that is always my first choice, though if you want to backup to prevent ransomware issues, I’d use rsnapshot since that will give you history.

If you are concerned about never ever losing a single email no matter what, then you need a replication server that supports versioning.

-- A cubicle is simply a cell without a door.