From owner-freebsd-scsi  Sat Oct 17 06:31:38 1998
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From: Wilko Bulte <wilko@yedi.iaf.nl>
Message-Id: <199810171023.MAA01923@yedi.iaf.nl>
Subject: Re: filesystem safety and SCSI disk write caching
In-Reply-To: <199810161632.LAA10179@bonkers.taronga.com> from Peter da Silva at "Oct 16, 98 11:32:57 am"
To: peter@taronga.com (Peter da Silva)
Date: Sat, 17 Oct 1998 12:23:04 +0200 (CEST)
Cc: scsi@FreeBSD.ORG
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As Peter da Silva wrote...
> In article <199810141501.JAA04936@mt.sri.com>,
> Nate Williams  <nate@mt.sri.com> wrote:
> >IMO, CAM should disable write caching by default, and allow people to
> >add it back by hand if they know how.  I don't know how this would be
> >done, but it's *ALWAYS* a better idea to be safe than to be sorry.
> 
> This seems like a no-brainer to me.
> 
> Does write-caching actually improve performance measurably? I would have
> assumed that FreeBSD would do a better job than any drive could, and it
> certainly has more resources available. Write-caching always seemed to be
> one of those Windows-oriented optimizations that were better avoided with
> real operating systems... unless the write-cache is something like the
> 128MB battery-backed cache in our Storageworks RAID box down the hall
> from me.

Your Storageworks box uses it's cache for more than just caching. What
type of HSZ controller does it have BTW?

Wilko
_     ______________________________________________________________________
 |   / o / /  _  Bulte 				  email: wilko@yedi.iaf.nl 
 |/|/ / / /( (_) Arnhem, The Netherlands          WWW  : http://www.tcja.nl
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