jfs_fscklog

jfs_fscklog [ -v ] [ -t ] [ -l logfile ] device

-v
    Enable verbose output with extra details

-t
    Prepend timestamps to each log line

-l logfile
    Write log to logfile instead of stdout

device
    JFS block device or raw image file

jfs_fscklog is a utility from the JFS (Journaled File System) toolsuite for Linux. It extracts and displays the fsck log stored in the JFS aggregate superblock. This log captures detailed information from the last run of jfs_fsck (or fsck.jfs), including errors detected, repairs performed, aggregate and filesystem mount information, and other diagnostics.

The tool is essential for troubleshooting JFS filesystem issues post-fsck, allowing admins to review check results without rerunning fsck. By default, it outputs the log to stdout in a human-readable format. Options enable writing to a file, prepending timestamps for better chronology, or verbose mode for additional details.

It operates directly on block devices or raw filesystem images, requiring read access to the superblock. No filesystem mount is needed, making it safe for use on unmounted volumes. Primarily used in enterprise environments where JFS was common on AIX ports to Linux.

Works only on JFS v1 filesystems; log shows last fsck run and may be cleared by subsequent checks or jfs_fsck -f. Requires superblock read access.

jfs_fscklog -t -l /tmp/fsck.log /dev/sdb1
Writes timestamped log from /dev/sdb1 to /tmp/fsck.log.

0 on success; non-zero if no log found, invalid device, or read error.

Part of JFSutils, developed by IBM's Sonny Parlin et al. for Linux port of AIX JFS (2001). Included in kernel packages until JFS deprecation around 2010s.

jfs_fsck(8), fsck.jfs(8), jfs_tune(8), jfs_debugfs(8)