'df' numbers discrepancy?

'df' numbers discrepancy?

Post by Mark Bratche » Wed, 12 Nov 2003 01:15:40



I just installed an 80GB drive on my RH Linux system, kernel 2.4.18.

My partition table for the drive looks like this per fdisk:

  Disk /dev/hdd: 16 heads, 63 sectors, 158816 cylinders
  Units = cylinders of 1008 * 512 bytes

     Device Boot    Start       End    Blocks   Id  System
  /dev/hdd1             1    158816  80043232+   5  Extended
  /dev/hdd5             1    134096  67584321   83  Linux
  /dev/hdd6        134097    158816  12458848+  83  Linux

And my 'df' output is this:

  Filesystem           1k-blocks      Used Available Use% Mounted on
  /dev/hdd6             12263312   3684760   7955612  32% /install
  /dev/hdd5             66523112  22399808  40744088  35% /backup

I don't understand why the "Used" and "Available" add up to a number
that is about 2GB smaller than the total blocks for /dev/hdd5. Is this normal?
I know that they don't typically add up, but the difference seemed large to me.
Can anyone explain the diff? Thanks.

--
Mark Bratcher
--------------------------------------------------------
Why choose Linux? Check out this Ernie Ball saga:
http://linux.bryanconsulting.com/stories/storyReader$172

 
 
 

'df' numbers discrepancy?

Post by Georg Ach » Wed, 12 Nov 2003 02:15:46




|> I don't understand why the "Used" and "Available" add up to a number
|> that is about 2GB smaller than the total blocks for /dev/hdd5. Is this normal?
|> I know that they don't typically add up, but the difference seemed large to me.
|> Can anyone explain the diff? Thanks.

Look at the manpage of mke2fs or tune2fs, especially the option "-m"...
--

         http://wwwbode.in.tum.de/~acher
         "Oh no, not again !" The bowl of petunias

 
 
 

'df' numbers discrepancy?

Post by Mark Bratche » Wed, 12 Nov 2003 04:51:08





>|> I don't understand why the "Used" and "Available" add up to a number
>|> that is about 2GB smaller than the total blocks for /dev/hdd5. Is this normal?
>|> I know that they don't typically add up, but the difference seemed large to me.
>|> Can anyone explain the diff? Thanks.

> Look at the manpage of mke2fs or tune2fs, especially the option "-m"...

Thanks Georg, makes perfect sense.

--
Mark Bratcher
--------------------------------------------------------
Why choose Linux? Check out this Ernie Ball saga:
http://linux.bryanconsulting.com/stories/storyReader$172

 
 
 

'df' numbers discrepancy?

Post by root » Wed, 12 Nov 2003 11:36:57



Quote:> I just installed an 80GB drive on my RH Linux system, kernel 2.4.18.

> My partition table for the drive looks like this per fdisk:

>   Disk /dev/hdd: 16 heads, 63 sectors, 158816 cylinders
>   Units = cylinders of 1008 * 512 bytes

>      Device Boot    Start       End    Blocks   Id  System
>   /dev/hdd1             1    158816  80043232+   5  Extended
>   /dev/hdd5             1    134096  67584321   83  Linux
>   /dev/hdd6        134097    158816  12458848+  83  Linux

> And my 'df' output is this:

>   Filesystem           1k-blocks      Used Available Use% Mounted on
>   /dev/hdd6             12263312   3684760   7955612  32% /install
>   /dev/hdd5             66523112  22399808  40744088  35% /backup

> I don't understand why the "Used" and "Available" add up to a number
> that is about 2GB smaller than the total blocks for /dev/hdd5. Is this
> normal? I know that they don't typically add up, but the difference
> seemed large to me. Can anyone explain the diff? Thanks.

I'd suspect that the differences can be accounted for if the blocks used
for inodes were assigned to the used column.

--
Cheers, Gene
A mostly retired old coot

 
 
 

'df' numbers discrepancy?

Post by RRB » Fri, 14 Nov 2003 00:31:38



> I just installed an 80GB drive on my RH Linux system, kernel 2.4.18.
...
>   Filesystem           1k-blocks      Used Available Use% Mounted on
>   /dev/hdd6             12263312   3684760   7955612  32% /install
>   /dev/hdd5             66523112  22399808  40744088  35% /backup

> I don't understand why the "Used" and "Available" add up to a number
> that is about 2GB smaller than the total blocks for /dev/hdd5. Is this normal?
> I know that they don't typically add up, but the difference seemed large to me.
> Can anyone explain the diff? Thanks.

I think this is the space reserver for root, about 5%.

Bye,Rrb sohe.