What is Linear Tape File System (LTFS)?

LTFS provides an industry standard format for recording data on modern magnetic tape.

LTFS is a file system that allows files stored on magnetic tape to be accessed in a similar fashion to those on disk or removable flash drives. LTFS refers to both the format of data recorded on magnetic tape media and the implementation of specific software that uses this data format to provide a file system interface to data stored on magnetic tape.

Magnetic tape data storage has been used for over 50 years, but typically did not hold file metadata in a form easy to access or modify independent of the file content data. Often external databases were used to maintain file metadata (file names, timestamps, directory hierarchy) to hold this data but these external databases were generally not designed for interoperability and tapes might or might not contain an index of their content.

The standard is based around a self-describing tape format originally developed by IBM.

The LTFS specification became part of the SNIA family of standards in 2012, donated by IBM to SNIA in order to become an open SNIA standard.

SNIA's Linear Tape File System (LTFS) Technical Work Group is focusing technical efforts on the development of the architecture that is related to the on-tape format for LTFS. The architecture also produces a comprehensive set of specifications ensuring a consistency of interface standards across LTFS related efforts.

The LTFS Format is approved as ISO standard ISO/IEC 20919:2016 and this is standard allows for the following:

  • File system implementations using tape
  • User-friendly access to tape data using familiar tools and interfaces
  • Cross-platform and cross-vendor interoperability for tape – Non-Proprietary
  • A standard for data interchange
  • Open markets
  • Ensures multivendor products
  • Data sharing

The LTFS Format is particularly suited to:

  • Data export and import
  • Data interchange and exchange
  • Direct file and partial file recall from sequential access media
  • Archival storage of files using a simplified, self-contained or “self-describing” format on sequential access media

The LTFS Format has these features:

  • An LTFS Volume can be mounted and volume content accessed with full use of the data without the need to access other information sources
  • Data can be passed between sites and applications using only the information written to an LTFS Volume
  • Files can be written to, and read from, an LTFS Volume using standard POSIX file operations.

LTFS Bulk Transfer Standard

The LTFS Bulk Transfer standard defines a method by which a set of files, directories and objects from a source system can be transferred to a destination system. The bulk transfer of large quantities of data is well suited for LTFS due to the economic and environmental characteristics of tape.

Building on top of the LTFS format, a standardized method for transferring data is defined that provides many advantages such as:

  • Provides a uniform way to initiate and accept transfers
  • Defines a manifest of which files are to be transferred, which communicates intent to transfer
  • Instructs how the files should be merged into the destination namespace
  • Facilitates the verification of the integrity and completeness of the transfer
  • Defines error handling and recovery behaviors
  • A recommended method for bulk transfers to/from or between cloud storage

The LTFS Bulk Transfer standard is specifically targeted for the following use cases:

  • An enterprise needs to transfer a large volume of data to or from a remote location
  • An enterprise needs to update or synchronize a subset of data stored at a remote location
  • An enterprise needs to transfer a large volume of data to a second enterprise, public, or private cloud
  • An enterprise needs to transfer a large volume of data from a public or private cloud
  • An enterprise needs to transfer a large volume of data from one public or private cloud to a second public or private cloud

Documents and Resources

Additional information about LTFS can be obtained using the links below: