From owner-freebsd-questions Thu Jan 2 13:50:27 2003 Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A9D6437B401; Thu, 2 Jan 2003 13:50:26 -0800 (PST) Received: from pit.databus.com (p70-227.acedsl.com [66.114.70.227]) by mx1.FreeBSD.org (Postfix) with ESMTP id C65D043EC2; Thu, 2 Jan 2003 13:50:25 -0800 (PST) (envelope-from barney@pit.databus.com) Received: from pit.databus.com (localhost [127.0.0.1]) by pit.databus.com (8.12.6/8.12.6) with ESMTP id h02LoI1N052364; Thu, 2 Jan 2003 16:50:18 -0500 (EST) (envelope-from barney@pit.databus.com) Received: (from barney@localhost) by pit.databus.com (8.12.6/8.12.6/Submit) id h02LoILU052363; Thu, 2 Jan 2003 16:50:18 -0500 (EST) (envelope-from barney) Date: Thu, 2 Jan 2003 16:50:18 -0500 From: Barney Wolff To: Bruce Evans Cc: Bruce Campbell , freebsd-hardware@FreeBSD.ORG, freebsd-questions@FreeBSD.ORG Subject: Re: Followup to "fallback to PIO mode" on dual processor AMD systems Message-ID: <20030102215018.GA52185@pit.databus.com> References: <1041526384.3e146e708b8e4@www.nexusmail.uwaterloo.ca> <20030103062516.F755-100000@gamplex.bde.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030103062516.F755-100000@gamplex.bde.org> User-Agent: Mutt/1.4i X-Scanned-By: MIMEDefang 2.26 (www . roaringpenguin . com / mimedefang) Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Fri, Jan 03, 2003 at 06:36:29AM +1100, Bruce Evans wrote: > > The fallback is clearly wrong because it turns isolated media errors > into pessimized i/o for the whole disk at best, system hangs during > resets next best, and system crashes at worst. I keep a disk with bad > media on line for testing some of this, and zap the fallback using the > following patch (hope this is complete; it was edited from a larger > patch). Perhaps the right answer is to test uptime and do the fallback if the error happens in the first minute, at least for permanently-mounted disks. In any case, retries in the current mode should be exhausted first. -- Barney Wolff http://www.databus.com/bwresume.pdf I'm available by contract or FT, in the NYC metro area or via the 'Net. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message