Work

Nesting Overlay File Systems with ShadowWhiteout

Year: 2025

Type: conference-paper

Abstract: Container technology improves storage efficiency by sharing base images through overlay file systems (overlayfs). Overlayfs enables temporary modifications while preserving original files by merging multiple directories into a single unified view. However, in container-in-container environments, the current overlayfs approach incurs inefficiency in terms of storage usage, as it does not support nesting due to file deletion operations. To delete a preserved original file, a special file is created indicating that the file is deleted in the overlayfs, but this mechanism lacks expressiveness for nesting. This paper introduces ShadowWhiteout, a new representation for file deletion in overlayfs. We identify key technical challenges and implement a ShadowWhiteout-capable overlayfs. Our system allows nesting overlayfs while maintaining reasonable runtime overhead.

Source: ACM SIGOPS Asia-Pacific Workshop on Systems (APSys)

DOI: 10.1145/3725783.3764408

Authors: Kenta Ishiguro, Kohei Hayama, Ayase Yokoyama, Hiroshi Yamada, Toshio Hirotsu

Institutions: Institut polytechnique de Grenoble, Université Grenoble Alpes, Hosei University, Tokyo University of Agriculture and Technology

Language: English

Topic: Advanced Data Storage Technologies

Subfield: Computer Networks and Communications

Field: Computer Science

Domain: Physical Sciences

Open Access status: green

Funder: Japan Science and Technology Agency

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