e2freefrag(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLE | AUTHOR | SEE ALSO | COLOPHON

E2FREEFRAG(8)            System Manager's Manual           E2FREEFRAG(8)

NAME         top

       e2freefrag - report free space fragmentation information

SYNOPSIS         top

       e2freefrag [ -c chunk_kb ] [ -h ] filesys

DESCRIPTION         top

       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         top

       -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         top

       # 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         top

       This version of e2freefrag was written by Rupesh Thakare, and
       modified by Andreas Dilger <adilger@sun.com>, and Kalpak Shah.

SEE ALSO         top

       debugfs(8), dumpe2fs(8), e2fsck(8)

COLOPHON         top

       This page is part of the e2fsprogs (utilities for ext2/3/4
       filesystems) project.  Information about the project can be found
       at ⟨http://e2fsprogs.sourceforge.net/⟩.  It is not known how to
       report bugs for this man page; if you know, please send a mail to
       man-pages@man7.org.  This page was obtained from the project's
       upstream Git repository
       ⟨git://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git⟩ on
       2021-04-01.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-02-28.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

E2fsprogs version 1.46.2      February 2021                E2FREEFRAG(8)