Which is the default storage driver used by Docker?

The default storage driver used by Docker is Overlay2. This driver is designed to be more efficient and provide better performance than its predecessors. Overlay2 builds on the overlay filesystem concept, allowing layers to be stacked on top of each other. This enables the efficient management of disk space since only the differences between layers need to be stored. Overlay2 handles file system changes effectively, offering features such as improved image management and support for container writable layers.

This choice has become the preferred option because of its compatibility and performance benefits, making it suitable for various Linux distributions. Its robust design reduces complexity and helps streamline container operations, which is why it has been adopted as the default in newer versions of Docker.