-*- nroff -*- 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 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
minimum/
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" Desired size of chunk. It is specified in units of kilobytes (KB). If no
chunk_kb is specified on the command line, then the default value is 1024KB.
-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%)
Chunk size: 1048576 bytes (256 blocks)
Total chunks: 5876
Free chunks: 463 (7.9%)
Min free chunk: 4 KB
Max free chunk: 24008 KB
Avg free chunk: 252 KB
HISTOGRAM OF FREE CHUNK SIZES:
Chunk Size Range : Free chunks 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)