Onramps typically come in two forms today, either a specific piece of hardware that is provided to you or as a software application that you load onto a server or into a virtual infrastructure. The most common use case of these devices is as a part of a backup or archive applications where data is written to a local device quickly so the backup job can complete and then replicate through the cloud as bandwidth allows. Most of the onramps use a hybrid model that leverages a local storage capability and then copies that data to the cloud.”]
Source: https://www.darkreading.com/database-security/how-to-get-data-to-the-cloud-onramps