From owner-cvs-all Mon Dec 6 22: 4: 9 1999 Delivered-To: cvs-all@freebsd.org Received: from alpo.whistle.com (alpo.whistle.com [207.76.204.38]) by hub.freebsd.org (Postfix) with ESMTP id 200F014D7D; Mon, 6 Dec 1999 22:04:06 -0800 (PST) (envelope-from julian@whistle.com) Received: from current1.whiste.com (current1.whistle.com [207.76.205.22]) by alpo.whistle.com (8.9.1a/8.9.1) with ESMTP id WAA95058; Mon, 6 Dec 1999 22:04:05 -0800 (PST) Date: Mon, 6 Dec 1999 22:04:04 -0800 (PST) From: Julian Elischer To: Mike Smith Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern kern_shutdown.c In-Reply-To: <199912070554.VAA00398@mass.cdrom.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk On Mon, 6 Dec 1999, Mike Smith wrote: > > > > > > On Mon, 6 Dec 1999, Mike Smith wrote: > > > > > msmith 1999/12/06 20:35:37 PST > > > Change the default poweroff delay from 0 to 5 seconds. This seems to be > > > adequate for the IDE disks that I have available for testing. Most seem > > > to wait between 1 and 3 seconds before flushing their caches. > > > > > We (whistle) added explicit commands to tell IDE drives to not cache > > writes.. > > I am not sure how generic they are.... > > Or whether they are at all desirable in the general case. > > A "better" fix would be to have the atadisk driver explicitly flush the > cache on each drive while it's shutting down. This is just an expedient > stopgap to save us in the meantime. Softupdates is pointless without this because Soft Updates cannot guarantee the state of the filesystem to be sane unless the disk does not lie about whether it has written to the disk. Soft updates also makes all the writes async, so who cares.. :-) More precisely, the order of the writes must be absolutly maintained and disks that buffer writes usually reserve the right to re-order adjacent writes. This is basically what we decided was needed in discussion with Kirk to make Soft Updates safe. (The whole point). Julian > > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message