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Re: command "du" reports wrong size ?
From: |
Steven |
Subject: |
Re: command "du" reports wrong size ? |
Date: |
Mon, 03 Oct 2005 11:41:32 +0800 |
User-agent: |
Mozilla Thunderbird 1.0 (X11/20050215) |
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.