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)