Silly question regarding "du" and "df".

Carsten Aulbert carsten at
Fri Jan 26 10:10:05 UTC 2007

Michael T. Richter wrote:

> So why do "du" and "df" report different amounts used?  And why do the
> numbers reported by "df" not add up?  (And why does System
> Monitor->Devices report for that drive a size of 73.4GB instead of 79
> but reports the same amount used as "df"?)  Is this a case of the man
> with two watches never knowing what time it is?

I guess you fell into the trap of 1000 Bytes per 1 kByte and 1024 Bytes
per 1 kByte.

Try 'du -sch --si *' and the numebrs may be different again.

The difference is basically:

prefix	difference
k	1024/1000-1=2.4%
M	(1024/1000)^2-1=4.9%
G	7.4%
T	10.0%

There are also some information on about that.


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