[CentOS] df command reports inaccurate results?

[William L. Maltby]

On Wed, 2008-07-23 at 15:09 +0200, Ralph Angenendt wrote:
> Sean Carolan wrote:
> > Can anyone help make sense of this?  This is an ext3 partition.  It's
> > only showing 403GB out of 426GB used, but then it says only 632MB
> > available?  Where'd the extra ~25GB go?
> 
> Those are the ~ 5% which are automatically reserved for root ...
> 
> man tune2fs

Further, there is some overhead for i-nodes and what not. I don't recall
if that is included or excluded in/from the df calculations.

A "df -i" will likely show a *very* large number of available i-nodes
and a small percent used. I've many times made a file system and reduced
the number of i-nodes substantially and gained a *lot* of space. Due
diligence is required: the profile of number of files, average files
sizes, temporary files during busiest parts of the day, ... must be
taken into consideration to derive a "safe" usable number. Get wrong and
you'll need some aspirin for the headache.

Also, when making the file system, reducing the amount reserved for root
is usually safe on today's larger drives, especially on a relatively
stable system/user base/file/system usage.

> 
> Ralph
> <snip sig stuff>

-- 
Bill