Minus on disk:-)

[Anders Troback]

Thanks BAS for the very good explanation!!!

\\troback

On Wed, 21 Mar 2007 15:40:22 -0500
"Brian A. Seklecki" <bseklecki at collaborativefusion.com> wrote:

> On Wed, 2007-03-21 at 21:11 +0100, Anders Troback wrote:
> > Disk status:
> > Filesystem  1K-blocks      Used    Avail Capacity  Mounted on
> > /dev/ad8s2a    253678    124556   108828    53%    /
> > devfs               1         1        0   100%    /dev
> > /dev/ad8s2g  35796214  16027612 16904906    49%    /home
> > /dev/ad8s2e   1012974        -6   931944    -0%    /tmp
> > /dev/ad8s2f  20308398  15124786  3558942    81%    /usr
> > /dev/ad8s2d   1012974    258006   673932    28%    /var
> > 
> > Hi,
> > 
> > I'm just curious about this! How can a FS have used -6 bytes?
> 
> By default, 8% of capacity is reserved for UID0 (root) and is not
> represented in df(1).  Read tunefs(8):
> 
>      -m minfree
>              Specify the percentage of space held back from normal
> users; the minimum free space threshold.  The default value used is
> 8%. Note that lowering the threshold can adversely affect perfor-
>              mance:
> 
>              o   Settings of 5% and less force space optimization to
> always be used which will greatly increase the overhead for file
>                  writes.
> 
>              o   The file system's ability to avoid fragmentation
> will be reduced when the total free space, including the reserve,
>                  drops below 15%.  As free space approaches zero,
> throughput can degrade by up to a factor of three over the performance
>                  obtained at a 10% threshold.
> 
>              If the value is raised above the current usage level,
> users will be unable to allocate files until enough files have been
> deleted to get under the higher threshold.
> 
> Try this in fstab(5):
> 
> md          /tmp        mfs rw,-s64m,-m0    2   0
> 
> ~BAS
> 
> > 
> > As I said this is not a problem, I'm just curios about how things
> > work (and can someone please tell me how to make that a -100 Gb:-))
> > 
> > Thanks!


-- 
Anders Trobäck
http://www.troback.com/
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