From owner-freebsd-stable Thu Sep 20 19:48:46 2001 Delivered-To: freebsd-stable@freebsd.org Received: from cain.gsoft.com.au (genesi.lnk.telstra.net [139.130.136.161]) by hub.freebsd.org (Postfix) with ESMTP id 2795B37B40F for ; Thu, 20 Sep 2001 19:48:42 -0700 (PDT) Received: from cain.gsoft.com.au (root@spare0.gsoft.com.au [203.38.152.114]) by cain.gsoft.com.au (8.8.8/8.8.8) with ESMTP id MAA23355; Fri, 21 Sep 2001 12:18:33 +0930 (CST) (envelope-from doconnor@gsoft.com.au) Message-ID: X-Mailer: XFMail 1.5.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <20010920211704.C7820@gateway.bogus> Date: Fri, 21 Sep 2001 12:18:32 +0930 (CST) From: "Daniel O'Connor" To: Nuno Teixeira Subject: RE: hw.ata.wc && hw.ata.tags && softupdates short question Cc: freebsd-stable@freebsd.org Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 20-Sep-2001 Nuno Teixeira wrote: > For what I heard, I concluded that we shouldn't use softupdates with write > cache turned on. The first time that I tried this I loose a lot of work > due to a power failure. You shouldn't use write caching, period. Well you can but if you lose power you WILL lose data. If you just want speed and care naught about your data go ahead :) (I guess a UPS would increase your confidence) > 1. Can I use softupdates with hw.ata.wc="1" and hw.ata.tags="1" safely? > > 2. Does hw.ata.tags="1" "allows write caching to be safely turned on really? No, write caching tells the drive "Please lie to me about command completion" so when the OS performs a write the drive caches it and says "yes that's on disk", when it isn't. --- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message