Hi,
ok, let me assume, that I have to import 2 TB of assets at once into the AEM DAM. First that means, that this importing itself is a project on its own. It requires design, coding, testing and validation; and in the end you need to have a system, which is capable to process this huge amount of data. Let's further assume, that we alredy have done that, and that we want to focus on the way how the assets are actually uploaded in the DAM.
First I would have a disucssion with the users about each and every step of the DAM asset update workflow. You really should eliminate all steps which are not required. Because a step less saves you time. And then I would create a custom mini-application inside AEM, which loads the assets from local disk (or any other location) to the DAM using the Asset API. This application will constantly monitor the system to prevent an overload, and it also writes constantly progress information in a logfile. It will allow you pause and resume the process. If it fails, it can recover gracefully and does not re-upload the same assets again.
In the end you will likely have a process, which takes some days to finish.
kind regards,
Jörg