This article outlines what operations in Terra have a GCP cost and how you will pay for GCP charges with a Terra billing project. It also explains the billing structure (GCP and Terra), how GCP calculates and bills Terra users for charges, and how Terra Billing projects act as a pass-through to pay for the GCP costs of your work in Terra. 

To learn more about these costs and how to control them when working on Terra, see this article. 

Contents

Understanding GCP fees in Terra 
The GCP/Terra billing structure in a nutshell
Billing projects on Terra versus GCP
What does access to billing resources allow you to do? and not do? 
Some billing examples
 

Understanding GCP fees in Terra 

The Terra platform is free to use; you can browse showcase workspaces and the Data Library free as soon as you register for an account. There are no fees for contacting or working with the Terra support team. However, there are GCP costs associated with operations in Terra such as:

• Storing data in workspace buckets (storage)
• Running workflows (compute)
• Running interactive analyses (Jupyter Notebooks; RStudio) (compute and disk)
  
• Accessing data in Requester Pays buckets (egress

Terra passes along GCP charges with no markup through a Terra Billing project (the links above will take you directly to the GCP pricing pages). 

The Terra/GCP billing structure in a nutshell

There are three levels to the cost structure in Terra. Each level has its own function, and users/collaborators can be included with different permissions at each level in order to do different things.

At the top is a GCP Billing account, which is what ultimately pays GCP for storage, compute and egress costs. At the bottom is a project workspace, where you actually do the work - store and move data or run an analysis. In between is a Terra Billing project, a pass through between GCP and Terra.

Terra Quirk - GCP costs are calculated per billing project, not per user

Each workspace has a Terra billing project, which you assign when you create it. The billing project is the pass-through that pays the GCP costs from the umbrella GCP Billing account. For GCP accounting, it doesn't matter who does the work, it only matters how much data storage, egressing or analysis is done in all the workspaces under a Terra billing project. Think of your workspace like a car. The cost to fill the car with  gas depends on how far the car has gone since the last fillup, not on who has been driving.

For example, the workspace below stores data for the Analysis, Visualization, and Informatics Lab-Space (AnVIL).  GCP storage fees are paid - by the GCP Billing account - via the workspace Billing project (highlighted). Note that the billing project here is sometimes called the "workspace".

What does access to billing resources allow you to do (and not do)?

Access to billing allows you to create resources in the level below. Owners control who can create Billing projects and workspaces by assigning the appropriate permissions (see the chart below).  

	Note: It is workspace permissions, not billing permissions, that allow you to accrue costs in Terra
	To learn more about how to manage resources (including billing), see this article.

Some billing user examples 

It's not always intuitive how this billing structure plays out. Below are three examples - and what happens in each case - to help clarify the structure of billing.