Re: Fragmentation (was: XFS NFS server Oops)

[Steeve McCauley <smccauley@max-t.com>]

On Wed, Mar 20, 2002 at 11:09:16AM -0600, Steve Lord wrote:
> On Tue, 2002-03-19 at 19:37, Federico Sevilla III wrote:
> Probably hold off for now on running fsr.
> 
> Look at the other numbers on the output. The actual and ideal are
> more interesting. If you look at these, the difference is the number
> of extra extents you have above the ideal case. Then ask how much
> data you have on the disk, dividing by the actual extent number
> gives you the average length of the extents. It is also possible
> that most of the fragmentation is restricted to a few files.

We were stressing some systems with 1.6TB drive arrays
and ended up with very full, very fragmented filesystems.
This led to fs corruption and/or sysstem instability when
the system ran out of memory.  Note that these systems
were running at 99.9% disk full and fragmentation factors
of 99.8%.  Obviously any sane admin would not run a system
in this state for long (insane admins, redundant?).

My question is can XFS can be configured to reserve
a chunk of disk for root only access?  I vaguely remember
setting up an HPUX system several years ago and specifying
that 5% of the disk should be reserved for administrative
purposes.  That might be a bit extreme with a 1.7TB drive
array, but you get the idea.  Is there anything like this
in xfs?

Thanks,

steeve

-- 
:wq