jfs_fsck

jfs_fsck [-n|-p|-y|-f] [-V] device

-n
    Causes jfs_fsck to run in 'no' mode. It checks the filesystem for errors without making any changes. It reports the errors it finds but does not attempt to repair them.

-p
    Causes jfs_fsck to automatically repair the filesystem if errors are found, without prompting the user for confirmation. Use with caution as it can potentially lead to data loss if the repair process is not handled correctly.

-y
    Causes jfs_fsck to assume 'yes' to all prompts. Similar to -p but it still prompts for errors with repair decisions that require more context. Use carefully, especially without understanding the error cases

-f
    Forces a full filesystem check, even if the filesystem is marked as clean. This is useful for detecting latent errors that might not be apparent during a regular check.

-V
    Prints the version number of jfs_fsck and exits.

device
    Specifies the device to check (e.g., /dev/sda1).

The jfs_fsck command is a utility used to check and repair inconsistencies in the Journaled File System (JFS) on Linux. It examines the filesystem's metadata and data structures, identifying and attempting to correct errors such as corrupted inodes, directory entries, or superblock information.

jfs_fsck can be run in several modes, ranging from read-only checks to fully interactive repair sessions. It's crucial to unmount the filesystem before running jfs_fsck to prevent further corruption. While automatic repair is possible, user intervention might be necessary in complex cases. Backup the filesystem before any attempt of automatic repair of the filesystem. In a production environment, it's recommended to run the filesystem consistency check on an unmounted filesystem, preferably in single-user mode or from a rescue disk.

Always unmount the JFS filesystem before running jfs_fsck. Using jfs_fsck on a mounted filesystem can cause severe data corruption.
Backups are very important before running this command

jfs_fsck returns an exit code indicating the result of the check and repair process. A return code of 0 indicates that no errors were found or that all errors were successfully repaired.
Non-zero exit codes indicate that errors were found and that manual intervention may be required.

While jfs_fsck aims to repair filesystem errors, it's important to acknowledge the potential for data loss during the repair process. In severe corruption cases, it might not be possible to recover all data. It is always crucial to have up-to-date backups before running any filesystem repair utility.

JFS (Journaled File System) was initially developed by IBM for AIX. It was later ported to Linux.
jfs_fsck is a tool specifically designed to maintain the consistency of JFS filesystems. While JFS was a popular choice, other filesystems have gained more popularity, such as ext4 and XFS.

mkfs.jfs(8), fsck(8), mount(8), umount(8)