OverlayFS

OverlayFS is a technology that allows multiple layers of filesystems to be combined into one unified view. Think of it like stacking transparent sheets: the top layer can be changed without affecting the layers below. This is useful in scenarios like containers or virtual environments, where changes are made temporarily or independently. The top layer holds modifications, while the lower layers remain read-only. When accessing files, the system presents a seamless view, showing the latest changes from the top layer and the original files beneath. This approach enables efficient storage, quick updates, and easy maintenance without copying large amounts of data.