From owner-freebsd-hackers Thu Oct 3 14:20:20 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 18B1B37B401 for ; Thu, 3 Oct 2002 14:20:19 -0700 (PDT) Received: from out7.mx.nwbl.wi.voyager.net (out7.mx.nwbl.wi.voyager.net [169.207.3.125]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9D57F43E77 for ; Thu, 3 Oct 2002 14:20:18 -0700 (PDT) (envelope-from silby@silby.com) Received: from pop2.nwbl.wi.voyager.net (pop2.nwbl.wi.voyager.net [169.207.3.115]) by out7.mx.nwbl.wi.voyager.net (Postfix) with ESMTP id A614193AFB; Thu, 3 Oct 2002 16:20:17 -0500 (CDT) Received: from [10.1.1.6] (d150.as15.nwbl0.wi.voyager.net [169.207.136.88]) by pop2.nwbl.wi.voyager.net (8.10.2/8.10.2) with ESMTP id g93LKG162817; Thu, 3 Oct 2002 16:20:16 -0500 (CDT) Date: Thu, 3 Oct 2002 16:25:07 -0500 (CDT) From: Mike Silbersack To: Sean Farley Cc: freebsd-hackers@freebsd.org Subject: Re: Slow I/O responsiveness with UDMA133 In-Reply-To: <20020930140925.G5254-100000@thor.farley.org> Message-ID: <20021003162004.L71443-100000@patrocles.silby.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG 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