e2freefrag(category5-qmail.html) - phpMan

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 informa-
       tion 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  mini-
       mum/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 AT sun.com>, and Kalpak Shah.
SEE ALSO
       debugfs(8), dumpe2fs(8), e2fsck(8)

E2fsprogs version 1.42.9         December 2013                   E2FREEFRAG(8)