[ILUG] Defragmenting

[Jeroen Massar]

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Jeroen Massar wrote:
> Lisa Muir wrote:
>> Just done a quick google to see if I can find a tool for defragmenting
>> a disk under linux, but all hits quickly refer to windows.
> 
>> Can anyone recommend such a tool?
> 
> Recommend no as Ext2/3 _should_ automatically defrag itself, so I
> actually never bothered doing one :)

Replying to self :) [who invented google, lets shoot them!]

I found:
http://www2.lut.fi/~ilonen/ext3_fragmentation.html
and:
http://www.informatik.uni-frankfurt.de/~loizides/reiserfs/fibmap.html

These tools can tell you how much fragmentation is happening on your disk.

Short test:
8<----------------------------------------------------------------
... see below ...
Non-contiguous:
  Files 63 (34631.0MB, avg. 562891.60kB per file), blocks 171345,
average block 206.96kB
Contiguous:
  Files 12 (0.1MB, avg. 8.73kB per file)
- ---------------------------------------------------------------->8

So that kind of empirically proves that ext3 *DOES* fragment.

# apt-get install defrag

defrag here I come, unfortunately it means you have to turn the disk
offline... (umounted)

Greets,
 Jeroen

- --
 64826 3832.6MB    60.54kB a
 34137 2766.2MB    82.98kB b
 17071  831.3MB    49.86kB c
 12442  686.5MB    56.50kB d
  8706  779.3MB    91.66kB e
  7299 4280.4MB   600.51kB f
  5238  699.5MB   136.74kB g
  3247 4480.8MB  1413.09kB h
  3110 4403.9MB  1450.03kB i
  2071  490.4MB   242.47kB j
  1691  626.5MB   379.40kB k
  1533  736.1MB   491.70kB l
  1396  616.3MB   452.05kB m
  1395  698.7MB   512.85kB o

eek 60k pieces... not good!
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