aufs

wikipedia:aufs (2006)

The contents of the /var/lib/docker/ directory vary depending on the driver Docker is using for storage.

By default this will be aufs but can fall back to overlay, overlay2, btrfs, devicemapper or zfs depending on your kernel support. In most places this will be aufs but the RedHats went with devicemapper.

Related

• Docker-compose: volumes:

See also

• overlay2
• File systems: ext4, XFS, ZFS, btrfs, wipefs, findfs, HDFS, overlay, aufs, virt-filesystems, Windows: (FAT, NTFS, ReFS), GPFS, squashfs, Ecryptfs, Encfs, FUSE, VMFS, Comparison of distributed file systems, Userspace filesystem, Resize filesystem size

https://stackoverflow.com/a/25978888/14175738