At the 2017 Vault storage conference, Amir Goldstein gave a talk about using overlayfs in a novel way to create snapshots for the underlying filesystem. His company, CTERA Networks, has used the NEXT3 ext3-based filesystem with snapshots, but customers want to be able to use larger filesystems than those supported by ext3. Thus he turned to overlayfs as a way to add snapshots for XFS and other local filesystems.