Globally unique resources that provide access to data management services and serve as the parent namespace for the services.
Take a look at this article about Migrating File Shares to Microsoft cloud. It was written sometime ago, so some figures could be outdated, but the context and details are still relevant.
What you can do to move the data to Azure, is to use Microsoft Azure Box. That way you can move your 57 TB data much more quickly. And once in Azure, you can use any migration tool to move them to SharePoint. It's much faster that day as the data will already be in Azure.