e2freefrag

Manual page and help for the e2freefrag Linux command Linux portal

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The manual page and help for the e2freefrag Linux command. E2freefrag is a command for reporting free space fragmentation on ext2 / 3/4 file systems. THE filesys option is the device name of the file system (eg / dev / hdc1, / dev / md0). The e2freefrag program examines the bitmap information of the block to check how many free blocks are present as adjacent and aligned free areas. THE chunk_approx represent the percentage of free blocks of different sizes. It also displays the minimum / maximum / average free piece size in the file system and the histogram of all free pieces. This information can be used to measure the fragmentation of free space in the file system.

 

 

Man page output

man e2freefrag
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 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
              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 1.44.5                                   December 2018                                              E2FREEFRAG(8)

 

 

Help output

sudo e2freefrag -h
usage: e2freefrag [-c chunksize in kb] [-h] device_name

 

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