file-access-time · shipping · also atime, File access timestamp, Last file access time

File access time

File access time (atime) is the filesystem timestamp associated with access to a file, subject to the operating system's access-time update policy.

On Linux, reads can update atime, but noatime suppresses access-driven updates and relatime limits them. With relatime, an access updates atime when the previous value is no later than mtime or ctime, or is more than a day old. O_NOATIME can suppress updates for an opened file. [1] [2]

lazytime is different: eligible timestamps are updated in memory while persistence may be deferred. Neither an unchanged atime nor delayed on-disk persistence proves that no access occurred. [2]

Relations

related
Inode, File modification time, Inode change time, File birth time

Advantages

  • Can indicate access relative to modification when the applicable update policy is known.

Limitations

  • May not record every read.
  • Can be set explicitly and is not a complete access log.

Citations

  1. Linux man-pages: inode(7) (accessed 2026-10-21)
  2. util-linux: mount(8), access-time policy and lazytime (accessed 2026-10-21)

Further reading

  1. Linux man-pages: utimensat(2) (accessed 2026-10-21)
  2. Hesela: interpreting file timestamps during rsync selection (accessed 2026-10-21)

JSON: /data/terms/file-access-time.json

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Hesela team. File access time. Hesela. 2026-10-21. https://hesela.dev/terms/file-access-time/