Date: Thu, 3 Oct 2002 16:25:07 -0500 (CDT) From: Mike Silbersack <silby@silby.com> To: Sean Farley <sean-freebsd@farley.org> Cc: freebsd-hackers@freebsd.org Subject: Re: Slow I/O responsiveness with UDMA133 Message-ID: <20021003162004.L71443-100000@patrocles.silby.com> In-Reply-To: <20020930140925.G5254-100000@thor.farley.org>
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On Mon, 30 Sep 2002, Sean Farley wrote: > On Thu, 26 Sep 2002 21:14, Mike Silbersack wrote: > > > Rumor has it that newer drives cannot write a single sector at a time, > > and instead must read a whole cluster of sectors, add in the new > > sector, and write back the whole cluster. That behavior sounds like > > it would hurt sequentual performance substantially, as it would become > > a lot of read-modify-write operations. > > That is interesting. I had not heard of that issue, even as a rumor, > before. I see this hurting byte writes, but block writes may not be > hurt by it. The concept isn't that ridiculous. If the drive cannot write 1 byte at a time, why should it be able to write 4096 bytes at a time, or 8192 bytes, etc. Unfortunately, I doubt that any drive manufacturer will tell us the exact figures. :) > You would not happen to have a non-RAID, UDMA100+, non-VIA system that > you could run bonnie++ (-s256) on? It would at least show to me if my > system is really all that far from the norm. > > Sean Nope, not here. Maybe someone else on the list can send you results... Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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