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e4defrag(8) [debian man page]

E4DEFRAG(8)						      System Manager's Manual						       E4DEFRAG(8)

e4defrag - online defragmenter for ext4 filesystem SYNOPSIS
e4defrag [ -c ] [ -v ] target ... DESCRIPTION
e4defrag reduces fragmentation of extent based file. The file targeted by e4defrag is created on ext4 filesystem made with "-O extent" option (see mke2fs(8)). 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 ext4 filesystem. If target is a directory, e4defrag reduces fragmen- tation of all files in it. If target is a device, e4defrag gets the mount point of it and reduces fragmentation of all files in this mount point. OPTIONS
-c Get a current fragmentation count and an ideal fragmentation count, and calculate fragmentation score based on them. By seeing this score, we can determine whether we should execute e4defrag to target. When used with -v option, the current fragmentation count and the ideal fragmentation count are printed for each file. Also this option outputs the average data size in one extent. If you see it, you'll find the file has ideal extents or not. Note that the maximum extent size is 131072KB in ext4 filesystem (if block size is 4KB). If this option is specified, target is never defragmented. -v Print error messages and the fragmentation count before and after defrag for each file. NOTES
e4defrag does not support swap file, files in lost+found directory, and files allocated in indirect blocks. When target is a device or a mount point, e4defrag doesn't defragment files in mount point of other device. Non-privileged users can execute e4defrag to their own file, but the score is not printed if -c option is specified. Therefore, it is desirable to be executed by root user. AUTHOR
Written by Akira Fujita <> and Takashi Sato <>. SEE ALSO
mke2fs(8), mount(8). e4defrag version 2.0 May 2009 E4DEFRAG(8)

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E2FREEFRAG(8)						      System Manager's Manual						     E2FREEFRAG(8)

e2freefrag - report free space fragmentation information SYNOPSIS
e2freefrag [ -c chunk_kb ] [ -h ] filesys DESCRIPTION
e2freefrag is used to report free space fragmentation on ext2/3/4 file systems. filesys is the filesystem device name (e.g. /dev/hdc1, /dev/md0). The e2freefrag program will scan the block bitmap information to check how many free blocks are present as contiguous and aligned free space. The percentage of contiguous free blocks of size and of alignment chunk_kb is reported. It also displays the mini- mum/maximum/average free chunk size in the filesystem, along with a histogram of all free chunks. This information can be used to gauge the level of free space fragmentation in the filesystem. OPTIONS
-c chunk_kb If a chunk size is specified, then e2freefrag will print how many free chunks of size chunk_kb are available in units of kilobytes (Kb). The chunk size must be a power of two and be larger than filesystem block size. -h Print the usage of the program. EXAMPLE
# e2freefrag /dev/vgroot/lvhome Device: /dev/vgroot/lvhome Blocksize: 4096 bytes Total blocks: 1504085 Free blocks: 292995 (19.5%) Min. free extent: 4 KB Max. free extent: 24008 KB Avg. free extent: 252 KB HISTOGRAM OF FREE EXTENT SIZES: Extent Size Range : Free extents Free Blocks Percent 4K... 8K- : 704 704 0.2% 8K... 16K- : 810 1979 0.7% 16K... 32K- : 843 4467 1.5% 32K... 64K- : 579 6263 2.1% 64K... 128K- : 493 11067 3.8% 128K... 256K- : 394 18097 6.2% 256K... 512K- : 281 25477 8.7% 512K... 1024K- : 253 44914 15.3% 1M... 2M- : 143 51897 17.7% 2M... 4M- : 73 50683 17.3% 4M... 8M- : 37 52417 17.9% 8M... 16M- : 7 19028 6.5% 16M... 32M- : 1 6002 2.0% AUTHOR
This version of e2freefrag was written by Rupesh Thakare, and modified by Andreas Dilger <>, and Kalpak Shah. SEE ALSO
debugfs(8), dumpe2fs(8), e2fsck(8) E2fsprogs version 1.42.5 July 2012 E2FREEFRAG(8)
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