[Breezy] Incorrect Report by df -h

[Tim Frost]

On Sat, 2005-12-31 at 13:10 -0800, Ed Fletcher wrote:
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> Hi All:
> 
> Happy New Year to everyone!
> 
> I'm cleaning up a couple of partitions and I'm not getting the results
> that I expected.  I enabled a root terminal with 'sudo -i' because one
> of the partitions wouldn't let me delete some of the directories.  I got
> rid of absolutely everything except for lost+found, which is empty.
> 
> This is what I end up with:
> 
> root:/mnt # df -h  (other partitions not shown)
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/sdb7             9.2G   33M  8.7G   1% /temp
> /dev/sda2              55G   33M   52G   1% /mnt
> root:/mnt #
> 
> The numbers don't add up.

This is normal.  Some space is reserved, so that ordinary users can't
fill a partition to 100% capacity.  The "Avail" column shows the space
available for non-root users.  If the partition is filled to the point
where the reserved space is being used, you will see Avail = 0.

> I know that they are empty.  In sda2 I get:
> 
> root:/mnt# ls -al
> total 24
> drwxr-xr-x   3 root    root   4096 Dec 31 12:48 .
> drwxr-xr-x  23 root    root   4096 Nov 29 19:26 ..
> drwx------   2 (owner) users 16384 Apr 23  2005 lost+found
> root:/mnt # cd lost+found/
> root:/mnt/lost+found # ls -al
> total 20
> drwx------  2 (owner) users 16384 Apr 23  2005 .
> drwxr-xr-x  3 root    root   4096 Dec 31 12:48 ..
> root:/mnt/lost+found #

Because the lost+found directory is used by fsck, it is normal for it to
be created with room for a number of entries.  This ensures that fsck
has space available in the filesystem to record inodes that don't have a
directory entry.


> 
> 'ls -al' shows that there are no files in this partition.  Doing the
> same check on sdb7 gives me the same result.  But 'df -h' shows almost
> the exact same result for sdb7 except that the blocks used by lost+found
> are 49152.
> 
> The sdb7 partition is ext3 and sda2 is ext2.  I don't see where the
> space is being used except that there are high block counts in
> lost+found in both partitions.  I can likely solve this by unmounting
> both and rewriting the filesystems, but that wouldn't solve the mystery
> for me.
> 
> Can anybody give me a hint as to what is happening here?

Reserved space plus room for recovery of lost inodes.
> 
> Many thanks,
> Ed
> - --
> Ed Fletcher
> ed at fletcher.ca
> 


Tim