Inconsistent disk/directory usage using 'ls'

essdeeay · 10-28-2005, 06:39 AM

Hello

I'm using FC3, and have noticed this anomoly on a few directories. When using the ls command, the size of the directory is nowhere near the size of the files within. For example, the file in here is larger that that reported for the size of it's parent:

Code:

[root@samba .maildir]# ls -alhR /home/tina/.maildir/new
/home/tina/.maildir/new:
total 440K
drwx------   2 tina tina  36K Oct 28 11:32 .
drwx------  13 tina tina 4.0K Oct 28 10:10 ..
-rw-------   1 tina tina 394K Oct 28 11:32 1130495528.Vfd00Ic07271.mydomain.org

And here, the size of the directory is way larger than the size of the file inside:

Code:

[root@samba .maildir]# ls -alhR /home/karen/.maildir/new
/home/karen/.maildir/new:
total 448K
drwx------   2 karen karen 424K Oct 28 12:06 .
drwx------  11 karen karen 4.0K Oct 28 11:54 ..
-rw-------   1 karen karen  14K Oct 28 12:06 1130497566.Vfd00Ic07219.mydomain.org

As far as I knew, the size of "." should always be 4K. These are IMAP folders (I'm using Dovecot) and I'm not sure if this is what IMAP is meant to do.

The reason I'm trying to work this out, is to check if the backups are being performed correctly (using rsync). I have a little script that counts the number of files, dirs and disk usage for a particular tree, and although the files/dirs numbers are the same for the real data and the backup, the disk usage is significantly different. So any other method to verify the backup is close enough to the real data will bypass this issue.

Kind regards,
Steve

MensaWater · 10-28-2005, 07:36 AM

Interesting. I did a test and found that "ls -lahR |grep ^dr" would give me the size of all the subdirectories and totaling those up would equal the size of "ls -lahd .".

Anyway a directory is a file in Linux/UNIX and sits within a filesystem more or less as a pointer to the files beneath it. It is NOT the size of the the files beneath it because if it were then a directory "file" would take up as much space as the total of all the files beneat it so you'd have to have double the space. If really interested you should reseach file handles and inodes to get more detail of the internal structure of filesystems.

Anyway what I think you're asking is how do you get a total for the space within a directory. The answer is with the "du" command. "du -sk <directory>" will give you the size of the space taken up by all the files within a given directory.