defragfs.ocfs2 - Man Page

online defragmenter for ocfs2 filesystem


defragfs.ocfs2 [-c] [-v] [-l] [-g] [-h][target]...


defragfs.ocfs2 reduces fragmentation of ocfs2 based file. The file targeted by defragfs.ocfs2 is created on ocfs2 filesystem The targeted file gets more contiguous blocks and improves the file access speed.

target is a regular file, a directory, or a device that is mounted as ocfs2 filesystem. If target is a directory, defragfs.ocfs2 reduces fragmentation of all files in it. If target is a device, defragfs.ocfs2 gets the mount point of it and reduces fragmentation of all files in this mount point.



Print the numbers of files that should be processed


verbose mode, the current fragmentation count and the ideal fragmentation count are printed for each file.

If this option is specified, target is never defragmented.


defragfs.ocfs2 will run in low io mode, which means it will regularly yield cpu to allow other processes to run.


defragfs.ocfs2 regularly records the current progress. So if it is interrupted, the next time you run defragfs.ocfs2 with this option, it will resume from the recorded progress.  Note that if this option is specified, other options are ignored and replaced by those that were recorded.


Print help info


defragfs.ocfs2 does not support files in lost+found directory. When target is a device or a mount point, defragfs.ocfs2 doesn't defragment files in mount point of other device.

It is completely not recommended to run against a file while it is actively in another application. Since the read/write of a file involves a dlm lock, this can result in a performance slowdown to both defragfs.ocfs2 and the application due to contention.

If the file system's free space is fragmented, or if there is insufficient free space available, defragfs.ocfs2 may not be able to improve the file's fragmentation.

Non-privileged users can execute defragfs.ocfs2 to their own file. Therefore, it is desirable to be executed by root user.


Written by Larry Chen <>


January 2012 Version 1.8.7 OCFS2 Manual Pages