[wellylug] Blocks count discrepancy fdisk & df

[Centurion Computer Technology (2005) Ltd]

On Sat, 2007-09-08 at 11:33 +1200, Carl Turney wrote:
> Hi,
> 
> I have a weird symptom on my system.  Here are the fdisk and df reports. 
> Take particular note of the massive difference between hda3 total blocks
> counts between the two, unlike for hda1 or hda2.
> 
> fdisk says ...
> 
> Disk /dev/hda: 80.0 GB, 80026361856 bytes
> 255 heads, 63 sectors/track, 9729 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  this line defines what fdisk terms
as blocks.  It appears to have cylinders containing 16065x 512 byte
blocks, so the raw partition block count is in units of 512 byte blocks.
>    Device Boot      Start         End      Blocks   Id  System
> /dev/hda1   *           1          13      104391   83  Linux
> /dev/hda2              14         138     1004062+  82  Linux swap / Solaris
> /dev/hda3             139        9729    77039707+  83  Linux
> df says ...
> 
> Filesystem           1K-blocks      Used Available Use% Mounted on
                               ^^^^^^^ See here df uses a measure of 1K
(1024 byte blocks) 
> /dev/hda3             37334192  20044920  15392800  57% /
> /dev/hda1               101086     13044     82823  14% /boot
> tmpfs                   257980         0    257980   0% /dev/shm

You also need to take into account that fdisk is talking about raw
partition size, and df is talking about blocks available for use (raw
size less inode tables, and less any reserved (root use only) blocks, so
this amount of space will always be less than the raw partition size.


-- 
Daniel Reurich

Centurion Computer Technology (2005) Limited.
Ph: 021 797 722