From owner-freebsd-questions Wed Mar 7 18: 6:19 2001 Delivered-To: freebsd-questions@freebsd.org Received: from guru.mired.org (okc-65-26-235-186.mmcable.com [65.26.235.186]) by hub.freebsd.org (Postfix) with SMTP id 9288E37B71B for ; Wed, 7 Mar 2001 18:06:14 -0800 (PST) (envelope-from mwm@mired.org) Received: (qmail 81684 invoked by uid 100); 8 Mar 2001 02:06:13 -0000 From: Mike Meyer MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15014.59669.718668.654739@guru.mired.org> Date: Wed, 7 Mar 2001 20:06:13 -0600 To: "Philip J. Koenig" Cc: questions@freebsd.org Subject: Re: SoftUpdates/hardware write cache In-Reply-To: <123006805@toto.iv> X-Mailer: VM 6.89 under 21.1 (patch 14) "Cuyahoga Valley" XEmacs Lucid X-face: "5Mnwy%?j>IIV\)A=):rjWL~NB2aH[}Yq8Z=u~vJ`"(,&SiLvbbz2W`;h9L,Yg`+vb1>RG% *h+%X^n0EZd>TM8_IB;a8F?(Fb"lw'IgCoyM.[Lg#r\ Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Philip J. Koenig types: > Apparently the new drive has the internal write cache turned off by > default. I'm about to enable SoftUpdates with the tunefs thing and I > was wondering if I should also enable the disk's internal write > cache. My experience in the past with other OS's says it can make a > big performance improvement. Generally, this isn't recommended. Soft updates *depend* on the device actually having written the data to disk when it claims it has, and in the order it specified. > This machine runs on a large UPS so power-loss isn't a big issue. Well, if you want to try it, go ahead. If you have the time, I'd be interested in timings for all four cases (softupdates yes/no, write cache yes/no). > I know there is some Unix program that can at least read mode pages, > I'm hoping it can set them too. My DOS program won't work on this > hardware and I'd hate to have to stick the drive on a Windows machine > to set that setting. :-) Camcontrol can do that for your scsi devices. http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message