It is documented that download database can only be used for files less than 2Gb in size.
The suggested solution is to backup the file using the server backup function and then enable file sharing to the backup directory and access the file that way.
Thanks, eoin. You are correct. The issue always is what to do with external container storage. So I brought them all back into the database (internal storage), copied it, then encrypted it (EAR), then uploaded it, and then changed container storage back to external.