Date: Fri, 11 May 2001 08:28:35 -0700 From: Mike Smith <msmith@freebsd.org> To: "Kevin Oberman" <oberman@es.net> Cc: Leon Breedt <ljb@devco.net>, freebsd-mobile@FreeBSD.ORG Subject: Re: slow IDE performance Message-ID: <200105111528.f4BFSZY01262@mass.dis.org> In-Reply-To: Your message of "Fri, 11 May 2001 08:08:43 PDT." <200105111508.f4BF8hc01120@ptavv.es.net>
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> The reason that disk cache was disabled is that many IDE disks are junk
> and don't deal with cache properly in many respects. As a result, use
> of write cache is placing the integrity of disk data in doubt and can
> lead to disastrous failure in the event of unexpected power failure.
This has nothing to do with "IDE disks being junk"; it has to do with
softupdates not dealing well with the situation where cached disk writes
aren't really completed.
> I see a 400% increase in the time required for some disk write
> operations with write cache disabled, so I bit the bullet and enabled
> it on my laptop. It does have a good battery backup, after all, but be
> sure that you understand the risks involved in the use of write cache
> on cheap disks.
Again, this has nothing to do with "cheap disks".
> It is VERY dangerous to use write cache on a desktop or server where
> there is no battery backup.
Kind of like picking your nose; there's a very real danger of puncturing
the back of your nasal cavity and scooping out a large gob of brain with
a fingernail if you sneeze just right, but the chances of this actually
happening to you are pretty damn small.
--
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also. But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view. [Dr. Fritz Todt]
V I C T O R Y N O T V E N G E A N C E
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