4 e2freefrag \- report free space fragmentation information
17 is used to report free space fragmentation on ext2/3/4 file systems.
19 is the filesystem device name (e.g.
20 .IR /dev/hdc1 ", " /dev/md0 ).
23 program will scan the block bitmap information to check how many free blocks
24 are present as contiguous and aligned free space. The percentage of contiguous
25 free blocks of size and of alignment
27 is reported. It also displays the minimum/maximum/average free chunk size in
28 the filesystem, along with a histogram of all free chunks. This information
29 can be used to gauge the level of free space fragmentation in the filesystem.
33 Desired size of chunk. It is specified in units of kilobytes (KB). If no
35 is specified on the command line, then the default value is 1024KB.
38 Print the usage of the program.
40 # e2freefrag /dev/vgroot/lvhome
42 Device: /dev/vgroot/lvhome
48 Free blocks: 292995 (19.5%)
50 Chunk size: 1048576 bytes (256 blocks)
54 Free chunks: 463 (7.9%)
57 Min. free extent: 4 KB
59 Max. free extent: 24008 KB
61 Avg. free extent: 252 KB
64 HISTOGRAM OF FREE EXTENT SIZES:
66 Extent Size Range : Free extents Free Blocks Percent
68 4K... 8K- : 704 704 0.2%
70 8K... 16K- : 810 1979 0.7%
72 16K... 32K- : 843 4467 1.5%
74 32K... 64K- : 579 6263 2.1%
76 64K... 128K- : 493 11067 3.8%
78 128K... 256K- : 394 18097 6.2%
80 256K... 512K- : 281 25477 8.7%
82 512K... 1024K- : 253 44914 15.3%
84 1M... 2M- : 143 51897 17.7%
86 2M... 4M- : 73 50683 17.3%
88 4M... 8M- : 37 52417 17.9%
90 8M... 16M- : 7 19028 6.5%
92 16M... 32M- : 1 6002 2.0%
94 This version of e2freefrag was written by Rupesh Thakare, and modified by
95 Andreas Dilger <adilger@sun.com>, and Kalpak Shah.