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)