Re: Harddisk performance degrading over time?

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Alex Pilosov <alex(at)pilosoft(dot)com>
Cc: Daniel Åkerud <zilch(at)home(dot)se>, Jason Earl <jdearl(at)yahoo(dot)com>, PostgreSQL-general <pgsql-general(at)postgresql(dot)org>
Subject: Re: Harddisk performance degrading over time?
Date: 2001-06-24 22:29:29
Message-ID: 200106242229.f5OMTT306365@candle.pha.pa.us
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> 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 :)

Yes, BSD is more "doesn't fragment much" rather than "self
defragmenting".

> 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.

Yes, thanks for the clarification.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
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