Docker supports several storage drivers, using a pluggable architecture.
The storage driver controls how images and containers are stored and managed on your Docker host
overlay2 is the preferred storage driver for all currently supported Linux distributions, and requires no extra configuration.
The legacy overlay driver was used for kernels that did not support the “multiple-lowerdir” feature required for overlay2 All currently supported Linux distributions now provide support for this, and it is therefore deprecated.
The aufs storage driver Was the preferred storage driver for Docker 18.06 and older, when running on Ubuntu 14.04 on kernel 3.13 which had no support for overlay2
The vfs storage driver is intended for testing purposes, and for situations where no copy-on-write filesystem can be used. Performance of this storage driver is poor, and is not generally recommended for production use.
fuse-overlayfsis preferred only for running Rootless Docker on a host that does not provide support for rootless overlay2 (Rootless mode allows running the Docker daemon and containers as a non-root user to mitigate potential vulnerabilities in the daemon and the container runtime.)
The btrfs and zfs storage drivers allow for advanced options, such as creating “snapshots”, but require more maintenance and setup. Each of these relies on the backing filesystem being configured correctly.