Re: command "du" reports wrong size ?

[Steven]

Hi Bob:
Thanks for your fast response.

Bob Proulx wrote:

> Steven wrote:
>  
>
> > I got a strange problem. i.e. "du" command reports wrong size in FC3/4,
> > dd --version
> > dd (coreutils) 5.2.1
> > du --version
> > du (coreutils) 5.2.1
> >    
>
> Thank you for your report and for including the respective version
> numbers and such.
>
>  
>
> > [fc3]~/tmp>dd if=/dev/zero of=dd.128 bs=1M count=128
> > 128+0 records in
> > 128+0 records out
> > [fc3]~/tmp>du -B 1M dd.128
> > 129 dd.128
> >
> > 129 != 128
> >    
>
> The 'du' command reports the amount of disk blocks used.  This is not
> quite the same thing as the size of the file.  You have created a file
> that is of a certain size.  But the filesystem may use more blocks to
> store it.  Because you are working on differnet machines I am guessing
> that the filesystems are different.
>
> What is the output of this command?
>
>  ls -ls dd.128
>
> What is the type of the filesystems involved?  You can use 'df -T' for
> this information.
>
>  df -T .
>
>  
[fc3]~/tmp>dd if=/dev/zero of=dd.128 bs=1M count=128
128+0 records in
128+0 records out
[fc3]~/tmp>ls -ls dd.128
131200 -rw-r--r--  1 steven steven 134217728 Oct  3 05:31 dd.128
[fc3]~/tmp>df -T
Filesystem    Type   1K-blocks      Used Available Use% Mounted on
/dev/hda1 reiserfs     2441712   2167580    274132  89% /
none         tmpfs       97464         0     97464   0% /dev/shm
/dev/hda3 reiserfs     1501836   1135296    366540  76% /home

> > However, if I use the dd and du in RedHat 9:
> > [rh9]~/tmp>dd --version
> > dd (coreutils) 4.5.3
> > [rh9]~/tmp>du --version
> > du (coreutils) 4.5.3
> >
> > [rh9]~/tmp>dd if=/dev/zero of=dd.128 bs=1M count=128
> > 128+0 records in
> > 128+0 records out
> > [rh9]~/tmp>du -B 1M dd.128
> > 128 dd.128
> >    
>
> Same thing here.  What is the output here?
>
>  ls -ls dd.128
>  df -T .
>
>  
[rh9]~/tmp>dd if=/dev/zero of=dd.128 bs=1M count=128
128+0 records in
128+0 records out

[rh9]~/tmp>ls -ls dd.128
131072 -rw-r--r--    1 steven   steven   134217728 Oct  3 10:06 dd.128

[rh9]~/tmp>df -T
Filesystem    Type   1K-blocks      Used Available Use% Mounted on
/dev/hda1 reiserfs    14658828   9925296   4733532  68% /
/dev/hda4 reiserfs    96178212  65544612  30633600  69% /home
none         tmpfs      451128         0    451128   0% /dev/shm

> > That's correct in RH9. Is that a bug of du in the coreutils 5.2.1 ? Or
> > where am I wrong ?
> >    
>
> Need more information to decide.  Types of filesystem and the sizes of
> the files.
>
> Bob
>  
Now I realized it's some overhead in the filesystem. Thanks again.

Steven.