jFS

JFS stands for Journaled File System, a family of file systems developed by IBM that use journaling to improve reliability after crashes. The original JFS was designed for IBM's AIX UNIX and records metadata changes in a journal before applying them to the main file system, enabling faster and more robust crash recovery.

A Linux version of JFS was ported by IBM and integrated into the Linux kernel, allowing Linux users to mount and manage JFS volumes alongside other file systems. A later generation, often referred to as JFS2, provides improvements such as support for larger volumes and files and more flexible metadata handling. JFS2 is used in IBM’s AIX and has been made available for Linux where supported.

Key features of JFS include metadata journaling to speed recovery, support for large file systems and large files, and the ability to grow a file system online. Depending on the implementation, JFS also offers support for quotas and extended attributes, contributing to its suitability for enterprise workloads. The design emphasizes data integrity and predictable performance on servers, particularly in environments requiring reliable, long-running storage.

Usage and availability vary by platform. In Linux, JFS can be mounted with the type jfs and is one option among others such as ext4, XFS, and btrfs for enterprise storage needs. While not as widely deployed on desktops as some other file systems, JFS remains part of IBM’s ecosystem and is valued for its crash-resilience and mature tooling in server settings.