misc/e2freefrag.8.in

   1 .\" -*- nroff -*-
   2 .TH E2FREEFRAG 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
   3 .SH NAME
   4 e2freefrag \- report free space fragmentation information
   5 .SH SYNOPSIS
   6 .B e2freefrag
   7 [
   8 .B \-c chunk_kb
   9 ]
  10 [
  11 .B \-h
  12 ]
  13 .B filesys
  14
  15 .SH DESCRIPTION
  16 .B e2freefrag
  17 is used to report free space fragmentation on ext2/3/4 file systems.
  18 .I filesys
  19 is the filesystem device name (e.g.
  20 .IR /dev/hdc1 ", " /dev/md0 ).
  21 The
  22 .B e2freefrag
  23 program will scan the block bitmap information to check how many free blocks
  24 are present as contiguous and aligned free space. The percentage of contiguous
  25 free blocks of size and of alignment
  26 .IR chunk_kb
  27 is reported.  It also displays the minimum/maximum/average free chunk size in
  28 the filesystem, along with a histogram of all free chunks.  This information
  29 can be used to gauge the level of free space fragmentation in the filesystem.
  30 .SH OPTIONS
  31 .TP
  32 .BI \-c " chunk_kb"
  33 If a chunk size is specified, then
  34 .B e2freefrag
  35 will print how many free chunks of size
  36 .I chunk_kb
  37 are available in units of kilobytes (Kb).  The chunk size must be a
  38 power of two and be larger than filesystem block size.
  39 .TP
  40 .BI \-h
  41 Print the usage of the program.
  42 .SH EXAMPLE
  43 # e2freefrag /dev/vgroot/lvhome
  44 .br
  45 Device: /dev/vgroot/lvhome
  46 .br
  47 Blocksize: 4096 bytes
  48 .br
  49 Total blocks: 1504085
  50 .br
  51 Free blocks: 292995 (19.5%)
  52 .br
  53
  54 Min. free extent: 4 KB
  55 .br
  56 Max. free extent: 24008 KB
  57 .br
  58 Avg. free extent: 252 KB
  59 .br
  60
  61 HISTOGRAM OF FREE EXTENT SIZES:
  62 .br
  63 Extent Size Range :   Free extents   Free Blocks  Percent
  64 .br
  65     4K...    8K- :           704           704     0.2%
  66 .br
  67     8K...   16K- :           810          1979     0.7%
  68 .br
  69    16K...   32K- :           843          4467     1.5%
  70 .br
  71    32K...   64K- :           579          6263     2.1%
  72 .br
  73    64K...  128K- :           493         11067     3.8%
  74 .br
  75   128K...  256K- :           394         18097     6.2%
  76 .br
  77   256K...  512K- :           281         25477     8.7%
  78 .br
  79   512K... 1024K- :           253         44914    15.3%
  80 .br
  81     1M...    2M- :           143         51897    17.7%
  82 .br
  83     2M...    4M- :            73         50683    17.3%
  84 .br
  85     4M...    8M- :            37         52417    17.9%
  86 .br
  87     8M...   16M- :             7         19028     6.5%
  88 .br
  89    16M...   32M- :             1          6002     2.0%
  90 .SH AUTHOR
  91 This version of e2freefrag was written by Rupesh Thakare, and modified by
  92 Andreas Dilger <adilger@sun.com>, and Kalpak Shah.
  93 .SH SEE ALSO
  94 .IR debugfs (8),
  95 .IR dumpe2fs (8),
  96 .IR e2fsck (8)