From owner-freebsd-stable Wed Mar 14 6:30: 2 2001 Delivered-To: freebsd-stable@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 B089C37B718 for ; Wed, 14 Mar 2001 06:29:56 -0800 (PST) (envelope-from mwm@mired.org) Received: (qmail 13706 invoked by uid 100); 14 Mar 2001 14:29:56 -0000 From: Mike Meyer MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15023.32868.9995.327616@guru.mired.org> Date: Wed, 14 Mar 2001 08:29:56 -0600 To: Mark Ibell Cc: Alfred Perlstein , Mars Attack , Soren Schmidt , Peter Wemm , Helge Oldach , oberman@es.net, mobile@FreeBSD.ORG, stable@FreeBSD.ORG Subject: Re: Disk I/O problem in 4.3-BETA In-Reply-To: <3AAF4DA0.C8DA9485@paradise.net.nz> References: <200103131007.f2DA73h54023@mobile.wemm.org> <01f001c0abaa$133e1680$4500a8c0@nomad> <20010313032635.Q29888@fw.wintelcom.net> <3AAF4DA0.C8DA9485@paradise.net.nz> 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-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Mark Ibell types: > What doesn't appear to have been mentioned is how exactly do we turn off > write caching on SCSI drives. From poking around the best I could work > out was to run 'camcontrol modepage da0 -m 0x08 -e -P 3' and set WCE to > 0 where 0x08 comes from /usr/share/misc/scsi_modes. > > Is this the correct way to do it? Assuming you've got the right numbers for WCE, yes. Camcontrol is the right tool. > Also, is it okay to leave tagged queuing enabled? (I'm really starting > to get paranoid after all this discussion!) I'd say yes, as at least some of the drivers expect it to be there. I think the critical thing is that the driver know when the data is actually on the disk, so if tagged queueing doesn't interfere with that, it's ok. 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-stable" in the body of the message