1 .TH E4DEFRAG 8 "May 2009" "e4defrag version 2.0"
3 e4defrag \- online defragmenter for ext4 filesystem
16 reduces fragmentation of extent based file. The file targeted by
18 is created on ext4 filesystem made with "-O extent" option (see
20 The targeted file gets more contiguous blocks and improves the file access
24 is a regular file, a directory, or a device that is mounted as ext4 filesystem.
29 reduces fragmentation of all files in it. If
33 gets the mount point of it and reduces fragmentation of all files in this mount
38 Get a current fragmentation count and an ideal fragmentation count, and
39 calculate fragmentation score based on them. By seeing this score, we can
40 determine whether we should execute
46 option, the current fragmentation count and the ideal fragmentation count are
47 printed for each file.
49 Also this option outputs the average data size in one extent. If you see it,
50 you'll find the file has ideal extents or not. Note that the maximum extent
51 size is 131072KB in ext4 filesystem (if block size is 4KB).
53 If this option is specified,
55 is never defragmented.
58 Print error messages and the fragmentation count before and after defrag for
62 does not support swap file, files in lost+found directory, and files allocated
63 in indirect blocks. When
65 is a device or a mount point,
67 doesn't defragment files in mount point of other device.
69 Non-privileged users can execute
71 to their own file, but the score is not printed if
73 option is specified. Therefore, it is desirable to be executed by root user.
75 Written by Akira Fujita <a-fujita@rs.jp.nec.com> and Takashi Sato
76 <t-sato@yk.jp.nec.com>.