Subject: Re: File caching absent?
To: Technolord <l.raiser@deathsdoor.com>
From: Manuel Bouyer <bouyer@antioche.lip6.fr>
List: netbsd-help
Date: 03/28/2000 18:54:04
On Tue, Mar 28, 2000 at 12:07:34PM +0200, Technolord wrote:
> 
> On my system (i386, 1.4.1) it looks like disk cache is absent:
> installing packages can take very long, removing directories can take
> even longer. du-ing twice takes 2x time.
> I wonder: is this supposed behaviour or I'm missing some configuration
> setting? Can I enable (at least read) file caching? If it is enabled,
> why doesn't it give any (apparent) pro? Is this only to i386 port or
> common to all other NetBSDs?

Of course NetBSD uses a cache. How much ram do you have ?

On NetBSD file meta-data writes are syncronous by default (can be changed with
a mount option). This guarantees that the filesystem is always in a coherent
state on disk (no need to 'fsck -y'), but directories entry creation/removal
take longer. You can enable complete async operation, but this is dangerous:
if your machine doesn't shutdown cleanly (hard reset, power shutdown, ...)
you may have to run fsck by hand, and this usually ends in lost of files
or directories ...
On -current you can enable soft-updates, which gives the speed of async
with the security of metadata sync.

--
Manuel Bouyer, LIP6, Universite Paris VI.           Manuel.Bouyer@lip6.fr
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