Re: [HACKERS] sorting big tables :(

On Thu, 21 May 1998, Oleg Broytmann wrote:

> Hello!
>
> On Wed, 20 May 1998, The Hermit Hacker wrote:
> > > No, that doesn't happen. The only way to eliminate fragmentation is a
> > > dump/newfs/restore cycle. UFS does do fragmentation avoidance (which is
> > > reason UFS filesystems have a 10% reserve).
> >
> > Okay, then we have two different understandings of this. My
> > understanding was that the 10% reserve gave the OS a 'temp area' in which
> > to move blocks to/from so that it could defrag on the fly...
>
> No, you are wrong. This 10% is temp area reserved for emergent
> situations - when root bring system down to single-user and do system
> maintainance.

Actually, in this one you are only partly right. Only root has
*access* to using that extra 10%, but, as I've been corrected by several
ppl, including a couple on the FreeBSD list, that 10% is meant to
*prevent/reduce* fragmentation.