From owner-freebsd-stable Thu Jun 17 13:43:44 1999 Delivered-To: freebsd-stable@freebsd.org Received: from uni4nn.gn.iaf.nl (osmium.gn.iaf.nl [193.67.144.12]) by hub.freebsd.org (Postfix) with ESMTP id DE171155B9 for ; Thu, 17 Jun 1999 13:43:41 -0700 (PDT) (envelope-from wilko@yedi.iaf.nl) Received: from yedi.iaf.nl (uucp@localhost) by uni4nn.gn.iaf.nl (8.9.2/8.9.2) with UUCP id WAA10028; Thu, 17 Jun 1999 22:18:36 +0200 (MET DST) Received: (from wilko@localhost) by yedi.iaf.nl (8.9.3/8.9.3) id UAA00996; Thu, 17 Jun 1999 20:50:40 +0200 (CEST) (envelope-from wilko) From: Wilko Bulte Message-Id: <199906171850.UAA00996@yedi.iaf.nl> Subject: Re: / not properly unmounted ? In-Reply-To: from Alfred Perlstein at "Jun 17, 1999 12: 7: 7 pm" To: bright@rush.net (Alfred Perlstein) Date: Thu, 17 Jun 1999 20:50:40 +0200 (CEST) Cc: chad@DCFinc.com, mike@smith.net.au, jedgar@fxp.org, sec@42.org, des@flood.ping.uio.no, freebsd-stable@FreeBSD.ORG X-Organisation: Private FreeBSD site - Arnhem, The Netherlands X-pgp-info: PGP public key at 'finger wilko@freefall.freebsd.org' X-Mailer: ELM [version 2.4ME+ PL43 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG As Alfred Perlstein wrote ... > On Thu, 17 Jun 1999, Chad R. Larson wrote: > > > As I recall, Mike Smith wrote: > > > > The first complaint was that the power-down was catching disk stuff > > > > still in cache. Setting an arbitrary delay on the way down seems > > > > inefficient at best, and possibly not sufficient. How about instead > > > > just making sure all buffers are flushed before the power-down is > > > > allowed to to occur, however long that takes? > > > > > > You can't do this, because it's the _disk_ that holds the cached data. > > > > Ok, I missed something in the original post? He's using some kind > > of caching (or RAID) controller? > > > > no, some drives have write caching, if you suddenly cut power, they > don't have enough charge left to write out the data in the cache. Volatile(*) writeback caches are a Bad Thing(tm). It escapes me why people can't get that message into their skulls. Sigh.. (*) volatile as in "not powerfailure protected. -- | / o / / _ Arnhem, The Netherlands - Powered by FreeBSD - |/|/ / / /( (_) Bulte WWW : http://www.tcja.nl http://www.freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message