E2FREEFRAG(8) System Manager's Manual E2FREEFRAG(8)
NAME
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 informa-
tion 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 <adilger@sun.com>, and Kalpak Shah.
SEE ALSO
debugfs(8), dumpe2fs(8), e2fsck(8)
E2fsprogs version 1.45.6 March 2020 E2FREEFRAG(8)