Date: Sun, 7 Sep 1997 09:59:54 +0200 (MEST) From: Søren Schmidt <sos@sos.freebsd.dk> To: dyson@FreeBSD.ORG Cc: michaelv@MindBender.serv.net, mal@algonet.se, current@FreeBSD.ORG Subject: Re: lousy disk perf. under cpu load (was IDE vs SCSI) Message-ID: <199709070759.JAA08253@sos.freebsd.dk> In-Reply-To: <199709070512.AAA00465@dyson.iquest.net> from "John S. Dyson" at "Sep 7, 97 00:12:32 am"
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In reply to John S. Dyson who wrote:
> Michael L. VanLoon -- HeadCandy.com said:
> >
> > Why is it necessary to bring this up over and over again.
> >
> Because I think that people sometimes think that the world changes
> from time to time. SCSI is really great in large high-end systems
> for sure. EIDE isn't the joke that IDE was 4-5yrs ago though.
No, it certainly is not..
Maybe I have to clarify something: Until recently I saw EIDE as a
joke, I have always seen SCSI to be _the_ solution. However, the
situation has changed ALOT in the last year. The ATA/ATAPI
protocol is getting cleaned up (but is still quite messy), they
have gotten real usable DMA in there, they are working on
overlapped cmd's (not quite there yet, but devices do exist).
I have done LOTS of tests on my humble little system which
clearly shows that EIDE/ATA4 has come of age...
> Here are my dd results for my EIDE 4GB Caviar drive -- NO STRIPING, running
> FreeBSD-current: I wonder how it would be to add a Promise EIDE controller,
> and run one drive per EIDE interface??? I do have one of those Promise
> controllers, and will probably add support in FreeBSD soon. Maybe I'll try
> ccd then :-).
I have two Maxtor 84000A6's one on each EIDE channel on a ASUS P6NP5, I've
played with ccd, ann you can get some VERY interesting numbers out of
that combo. I'll have to backup my system someday so I can do it again
and provide som numbers...
> Sorry that I didn't have time for a scientific measurement,
> but I would be interested in running some packaged benchmarks. (BTW,
> the command overhead for my 4GB Caviar is about 80-100usecs also... Older
> Caviars get about 200-400usecs.) My 2GB Hawk with an NCR controller gets
> about 800usecs. IDE isn't a toy any more, but it also isn't for every
> application either.
Hmm, if we then get ocerlapped cmd to work, we have a real screamer..
No, EIDE is certainly not a toy any more, the times they are achangeing...
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Søren Schmidt (sos@FreeBSD.org) FreeBSD Core Team
Even more code to hack -- will it ever end
..
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