That's too easy :) Just go to Akeeba Backup, Configuration, find the Data Processing Engine row and click on the Configure button next to it. Uncheck the "Delete files after upload" checkbox. There you go! The backup archives will be stored in both Dropbox and the server.
If you want something more complicated, e.g. a backup going in both Dropbox and S3, you will have to create two backup profiles and have two CRON jobs run one after the other (but not at the same time), each one running a new backup with its own profile.
Nicholas K. Dionysopoulos
Lead Developer and Director
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