Which tool is directly integrated into Azure file shares for migration purposes?

Azure File Sync is designed specifically to enable seamless integration of on-premises file servers with Azure file shares for migration and data synchronization purposes. By deploying Azure File Sync, administrators can extend their on-premises file shares to Azure while keeping a local cache of frequently accessed files. This allows for smooth and efficient migrations, as files can be transitioned to the cloud while maintaining access to local copies, thereby minimizing disruption to users.

This solution also provides additional benefits such as tiered storage, automated backup, and disaster recovery capabilities. Azure File Sync is particularly useful for organizations that need to leverage both local and cloud storage in a hybrid environment, thereby facilitating easier data management and access.

In terms of context for the other choices, RoboCopy is a file copying utility that is effective for migrating files but does not integrate natively with Azure services for ongoing sync or management. Data Box is a physical service for transferring large amounts of data to Azure, which is not tailored for ongoing file share integration. The Storage Migration Assistant, while a useful tool for migrating on-premises storage to Azure, is primarily focused on coordinating migrations to Azure file shares but does not provide the ongoing integration and synchronization that Azure File Sync offers.