1E2FREEFRAG(8) System Manager's Manual E2FREEFRAG(8)
2
6 e2freefrag - report free space fragmentation information
7
9 e2freefrag [ -c chunk_kb ] [ -h ] filesys
10
13 e2freefrag is used to report free space fragmentation on ext2/3/4 file
14 systems. filesys is the filesystem device name (e.g. /dev/hdc1,
15 /dev/md0). The e2freefrag program will scan the block bitmap informa‐
16 tion to check how many free blocks are present as contiguous and
17 aligned free space. The percentage of contiguous free blocks of size
18 and of alignment chunk_kb is reported. It also displays the mini‐
19 mum/maximum/average free chunk size in the filesystem, along with a
20 histogram of all free chunks. This information can be used to gauge
21 the level of free space fragmentation in the filesystem.
22
24 -c chunk_kb
25 If a chunk size is specified, then e2freefrag will print how
26 many free chunks of size chunk_kb are available in units of
27 kilobytes (Kb). The chunk size must be a power of two and be
28 larger than filesystem block size.
29 -h Print the usage of the program.
31
33 # e2freefrag /dev/vgroot/lvhome
34 Device: /dev/vgroot/lvhome
35 Blocksize: 4096 bytes
36 Total blocks: 1504085
37 Free blocks: 292995 (19.5%)
38 Min. free extent: 4 KB
40 Max. free extent: 24008 KB
41 Avg. free extent: 252 KB
42 HISTOGRAM OF FREE EXTENT SIZES:
44 Extent Size Range : Free extents Free Blocks Percent
45 4K... 8K- : 704 704 0.2%
46 8K... 16K- : 810 1979 0.7%
47 16K... 32K- : 843 4467 1.5%
48 32K... 64K- : 579 6263 2.1%
49 64K... 128K- : 493 11067 3.8%
50 128K... 256K- : 394 18097 6.2%
51 256K... 512K- : 281 25477 8.7%
52 512K... 1024K- : 253 44914 15.3%
53 1M... 2M- : 143 51897 17.7%
54 2M... 4M- : 73 50683 17.3%
55 4M... 8M- : 37 52417 17.9%
56 8M... 16M- : 7 19028 6.5%
57 16M... 32M- : 1 6002 2.0%
58
60 This version of e2freefrag was written by Rupesh Thakare, and modified
61 by Andreas Dilger <adilger@sun.com>, and Kalpak Shah.
62
64 debugfs(8), dumpe2fs(8), e2fsck(8)
65E2fsprogs version 1.45.3 July 2019 E2FREEFRAG(8)