From owner-freebsd-questions@FreeBSD.ORG Wed Jan 26 22:58:18 2005 Return-Path: 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 6CB1A16A4CE for ; Wed, 26 Jan 2005 22:58:18 +0000 (GMT) Received: from obsecurity.dyndns.org (CPE0050040655c8-CM00111ae02aac.cpe.net.cable.rogers.com [69.199.47.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3611F43D49 for ; Wed, 26 Jan 2005 22:58:18 +0000 (GMT) (envelope-from kris@obsecurity.org) Received: by obsecurity.dyndns.org (Postfix, from userid 1000) id A017651462; Wed, 26 Jan 2005 14:58:17 -0800 (PST) Date: Wed, 26 Jan 2005 14:58:17 -0800 From: Kris Kennaway To: "Terry R. Friedrichsen" Message-ID: <20050126225817.GA62727@xor.obsecurity.org> References: <200501262253.j0QMrkOJ043661@uplift.hosp.misyshealthcare.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="fdj2RfSjLxBAspz7" Content-Disposition: inline In-Reply-To: <200501262253.j0QMrkOJ043661@uplift.hosp.misyshealthcare.com> User-Agent: Mutt/1.4.2.1i cc: freebsd-questions@freebsd.org Subject: Re: FreeBSD 5.3 file system troubles X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Jan 2005 22:58:18 -0000 --fdj2RfSjLxBAspz7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jan 26, 2005 at 03:53:46PM -0700, Terry R. Friedrichsen wrote: > I wrote: >=20 > >> try running something that works the file system and simply turn off t= he > >> system power in the middle of it. >=20 > to which kris@obsecurity.org replied: >=20 > > This is expected if you don't turn off write caching of the hard > > disks. It breaks the softupdates consistency model because data > > written to the disk may not actually be written to the disk, so it's > > not there following an unexpected power cycle. Unfortunately write > > caching causes a performance hit, and there was a large user backlash > > when it was briefly enabled by default some years ago. >=20 > What you say is true, but what I'm observing is far worse than simply > missing the last few blocks of output files, etc. >=20 > The last time I had to power-cycle the Alpha box (because Xorg hung it), > it rebooted to single-user mode but I couldn't even run "sh" because > some file in lib was missing. Or if I *do* get into "sh" to run fsck, > it finds *hundreds and hundreds* of problems ... Some disks are also known to go crazy and scribble everywhere when they lose power. Kris --fdj2RfSjLxBAspz7 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (FreeBSD) iD8DBQFB+CCJWry0BWjoQKURAq5/AKC2BfHVi1nMk5pu6OczkdS8tGJ4owCeKcMK crSDx84vc0lAHeOcuFvKo5o= =LuBk -----END PGP SIGNATURE----- --fdj2RfSjLxBAspz7--