From owner-freebsd-stable Wed Mar 14 6: 5:48 2001 Delivered-To: freebsd-stable@freebsd.org Received: from aslan.scsiguy.com (aslan.scsiguy.com [63.229.232.106]) by hub.freebsd.org (Postfix) with ESMTP id 2BC8437B719; Wed, 14 Mar 2001 06:05:43 -0800 (PST) (envelope-from gibbs@scsiguy.com) Received: from scsiguy.com (localhost [127.0.0.1]) by aslan.scsiguy.com (8.11.2/8.9.3) with ESMTP id f2EE5Ks71827; Wed, 14 Mar 2001 07:05:21 -0700 (MST) (envelope-from gibbs@scsiguy.com) Message-Id: <200103141405.f2EE5Ks71827@aslan.scsiguy.com> X-Mailer: exmh version 2.2 06/23/2000 with nmh-1.0.4 To: Alfred Perlstein Cc: Helge Oldach , oberman@es.net, sos@freebsd.dk, mobile@FreeBSD.ORG, stable@FreeBSD.ORG Subject: Re: Disk I/O problem in 4.3-BETA In-Reply-To: Your message of "Tue, 13 Mar 2001 00:58:11 PST." <20010313005811.J29888@fw.wintelcom.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 14 Mar 2001 07:05:20 -0700 From: "Justin T. Gibbs" Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >First off, some disk caches are getting > 10megs, that's a lot >of potnetial seeking after loosing power depending on the cache >contents... I've heard that most modern drives reserve a contiguous area of the disk the size of the cache near where the heads park to dump any cache contents on power outage. This avoids most if not all seeking. When the disk powers up again, the reserve track is read and the transactions are written to the correct locations. Any disk that does this should be safe to use with write caching enabled. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message