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97 lines
2.5 KiB
Groff
97 lines
2.5 KiB
Groff
.\" -*- nroff -*-
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.TH E2FREEFRAG 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
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.SH NAME
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e2freefrag \- report free space fragmentation information
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.SH SYNOPSIS
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.B e2freefrag
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[
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.B \-c chunk_kb
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]
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[
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.B \-h
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]
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.B filesys
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.SH DESCRIPTION
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.B e2freefrag
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is used to report free space fragmentation on ext2/3/4 file systems.
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.I filesys
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is the filesystem device name (e.g.
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.IR /dev/hdc1 ", " /dev/md0 ).
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The
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.B e2freefrag
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program will scan the block bitmap information to check how many free blocks
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are present as contiguous and aligned free space. The percentage of contiguous
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free blocks of size and of alignment
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.IR chunk_kb
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is reported. It also displays the minimum/maximum/average free chunk size in
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the filesystem, along with a histogram of all free chunks. This information
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can be used to gauge the level of free space fragmentation in the filesystem.
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.SH OPTIONS
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.TP
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.BI \-c " chunk_kb"
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If a chunk size is specified, then
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.B e2freefrag
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will print how many free chunks of size
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.I chunk_kb
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are available in units of kilobytes (Kb). The chunk size must be a
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power of two and be larger than filesystem block size.
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.TP
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.BI \-h
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Print the usage of the program.
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.SH EXAMPLE
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# e2freefrag /dev/vgroot/lvhome
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.br
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Device: /dev/vgroot/lvhome
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.br
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Blocksize: 4096 bytes
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.br
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Total blocks: 1504085
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.br
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Free blocks: 292995 (19.5%)
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.br
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Min. free extent: 4 KB
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.br
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Max. free extent: 24008 KB
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.br
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Avg. free extent: 252 KB
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.br
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HISTOGRAM OF FREE EXTENT SIZES:
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.br
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Extent Size Range : Free extents Free Blocks Percent
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.br
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4K... 8K- : 704 704 0.2%
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.br
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8K... 16K- : 810 1979 0.7%
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.br
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16K... 32K- : 843 4467 1.5%
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.br
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32K... 64K- : 579 6263 2.1%
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.br
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64K... 128K- : 493 11067 3.8%
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.br
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128K... 256K- : 394 18097 6.2%
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.br
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256K... 512K- : 281 25477 8.7%
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.br
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512K... 1024K- : 253 44914 15.3%
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.br
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1M... 2M- : 143 51897 17.7%
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.br
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2M... 4M- : 73 50683 17.3%
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.br
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4M... 8M- : 37 52417 17.9%
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.br
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8M... 16M- : 7 19028 6.5%
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.br
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16M... 32M- : 1 6002 2.0%
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.SH AUTHOR
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This version of e2freefrag was written by Rupesh Thakare, and modified by
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Andreas Dilger <adilger@sun.com>, and Kalpak Shah.
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.SH SEE ALSO
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.IR debugfs (8),
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.IR dumpe2fs (8),
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.IR e2fsck (8)
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