thinfile

Thinfile is a term used in information technology to describe a lightweight file construct designed to minimize data footprint and input/output overhead. In practice, a thinfile stores a minimal header and a reference to the actual data blocks kept in a separate storage area, allowing applications to present a file interface without embedding the full payload inline.

Characteristics of thinfiles typically include a small metadata header, a content-addressable identifier or pointer, and links to a data store. They may omit embedded payload data entirely, relying on the data store to supply content on access. Implementation approaches vary, ranging from small metadata files that map to a blob store to copy-on-write references within a deduplicated or versioned storage system.

Thinfiles are commonly associated with architectures that emphasize data deduplication, content-addressable storage, or snapshotting. They can reduce storage overhead when many files share identical or nearby data blocks and can speed certain operations by limiting immediate data transfer. However, the indirection required to retrieve payload data can introduce performance costs and complexity, and the approach depends on the availability and reliability of the underlying data store.

Usage scenarios include backup and archival systems, large-scale file systems that employ deduplication, and applications that separate metadata management from actual data blocks. Thinfiles are not universally standardized, and their exact structure and behavior depend on the specific storage stack or application.

See also: sparse files, copy-on-write, deduplication, content-addressable storage, thin provisioning.