Key Terms

This page provides and overview of concepts used by Storage Transfer Service to describe how it works.

Storage Transfer Service relies, uses, and stores data in Cloud Storage. For a more complete understanding of Storage Transfer Service and Cloud Storage, see Cloud Storage Key terms.

Data source

A data source is a location where your data currently resides. Examples of a data source include:

  • An Amazon S3 bucket
  • A Microsoft Azure Blob Storage container
  • Another Cloud Storage bucket
  • A file system within your control
  • An HTTP/HTTPS location

We use the data source as the origin of a transfer.

Data sink

A data sink is a location that you want to transfer your data. When you use Storage Transfer Service to perform a transfer, the data sink is a Cloud Storage bucket.

Transfer operation

A transfer operation performs the work to copy data from a data source into a Cloud Storage bucket.

Transfer job

A transfer job schedules and configures one or more transfer operations. Transfer jobs can be as simple as a one-time job to move data from a data source into a Cloud Storage bucket, or as complex as a periodic synchronization from your data source to Cloud Storage.


On-premises means that your data source is within your direct control. These are machines that you are directly responsible for maintaining or administering. The machines may be located on your local premises or in a remote data center that you control. As long as you can log in and directly control the machines, we consider them on-premises.


An agent is software that we provide, in the form of a Docker container, for on-premises transfers. You install and run one or more agents on each machine you want to transfer data from, and monitor the agents from the Google Cloud Console.

Service Account

A service account is a special kind of account used by an application or a virtual machine (VM) instance, not a person. Storage Transfer Service uses a Google-managed service account to access your Cloud Storage resources. You grant permissions to the service account to access your Cloud Storage source or destination buckets, which enables Storage Transfer Service to transfer your data.