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0b2681f4 1.\" -*- nroff -*-
ffd80782 2.TH E2FREEFRAG 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
0b2681f4
TT
3.SH NAME
4e2freefrag \- report free space fragmentation information
5.SH SYNOPSIS
6.B e2freefrag
7[
8.B \-c chunk_kb
9]
10[
11.B \-h
12]
13.B filesys
14
15.SH DESCRIPTION
16.B e2freefrag
17is used to report free space fragmentation on ext2/3/4 file systems.
18.I filesys
19is the filesystem device name (e.g.
20.IR /dev/hdc1 ", " /dev/md0 ).
21The
22.B e2freefrag
23program will scan the block bitmap information to check how many free blocks
24are present as contiguous and aligned free space. The percentage of contiguous
25free blocks of size and of alignment
26.IR chunk_kb
27is reported. It also displays the minimum/maximum/average free chunk size in
28the filesystem, along with a histogram of all free chunks. This information
29can be used to gauge the level of free space fragmentation in the filesystem.
30.SH OPTIONS
31.TP
32.BI \-c " chunk_kb"
cba91c4b
TT
33If a chunk size is specified, then
34.B e2freefrag
35will print how many free chunks of size
0b2681f4 36.I chunk_kb
cba91c4b
TT
37are available in units of kilobytes (Kb). The chunk size must be a
38power of two and be larger than filesystem block size.
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TT
39.TP
40.BI \-h
41Print the usage of the program.
42.SH EXAMPLE
43# e2freefrag /dev/vgroot/lvhome
44.br
45Device: /dev/vgroot/lvhome
46.br
47Blocksize: 4096 bytes
48.br
ad751f11 49Total blocks: 1504085
0b2681f4 50.br
ad751f11 51Free blocks: 292995 (19.5%)
0b2681f4 52.br
0b2681f4 53
aff2cf8e 54Min. free extent: 4 KB
0b2681f4 55.br
aff2cf8e 56Max. free extent: 24008 KB
0b2681f4 57.br
aff2cf8e 58Avg. free extent: 252 KB
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TT
59.br
60
aff2cf8e 61HISTOGRAM OF FREE EXTENT SIZES:
0b2681f4 62.br
aff2cf8e 63Extent Size Range : Free extents Free Blocks Percent
0b2681f4 64.br
ad751f11 65 4K... 8K- : 704 704 0.2%
0b2681f4 66.br
ad751f11 67 8K... 16K- : 810 1979 0.7%
0b2681f4 68.br
ad751f11 69 16K... 32K- : 843 4467 1.5%
0b2681f4 70.br
ad751f11 71 32K... 64K- : 579 6263 2.1%
0b2681f4 72.br
ad751f11 73 64K... 128K- : 493 11067 3.8%
0b2681f4 74.br
ad751f11 75 128K... 256K- : 394 18097 6.2%
0b2681f4 76.br
ad751f11 77 256K... 512K- : 281 25477 8.7%
0b2681f4 78.br
ad751f11 79 512K... 1024K- : 253 44914 15.3%
0b2681f4 80.br
ad751f11 81 1M... 2M- : 143 51897 17.7%
0b2681f4 82.br
ad751f11 83 2M... 4M- : 73 50683 17.3%
0b2681f4 84.br
ad751f11 85 4M... 8M- : 37 52417 17.9%
0b2681f4 86.br
ad751f11 87 8M... 16M- : 7 19028 6.5%
0b2681f4 88.br
ad751f11 89 16M... 32M- : 1 6002 2.0%
0b2681f4
TT
90.SH AUTHOR
91This version of e2freefrag was written by Rupesh Thakare, and modified by
92Andreas Dilger <adilger@sun.com>, and Kalpak Shah.
93.SH SEE ALSO
94.IR debugfs (8),
95.IR dumpe2fs (8),
96.IR e2fsck (8)