Re: Harddisk performance degrading over time?

On Sun, 24 Jun 2001, Bruce Momjian wrote:

> > Oh yeah,
> > vacuuming is not the problem here.
> >
> > Thanks anyway... :)
> >
> > And also, it seems that it is the indexed searches that is suffering the
> > most. The non-indexed searches is less affected. This is not only PostgreSQL
> > but also MySQL.
>
> I know the BSD filesystems are self-defragmenting.  I don't know if the
> ext2 filesystems are the same.  Surely someone must know.
Not exactly, BSD ffs (fast filesystem) isn't self-defragmenting, it just
fragments differently [less than] ext2 :)

See this for paper and some tools to get ffs fragmentation stats:
http://www.eecs.harvard.edu/~margo/usenix.195
(it has links to critique of the paper as well)

There's a tool ftp://ftp.uk.linux.org/pub/linux/sct/defrag/ to defrag ext2
filesystem, but its considered to be alpha quality and not really
maintained.