From owner-freebsd-fs@FreeBSD.ORG Fri Apr 18 17:36:05 2003 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E338837B405; Fri, 18 Apr 2003 17:36:05 -0700 (PDT) Received: from HAL9000.homeunix.com (12-233-57-131.client.attbi.com [12.233.57.131]) by mx1.FreeBSD.org (Postfix) with ESMTP id E2D7743FE9; Fri, 18 Apr 2003 17:36:04 -0700 (PDT) (envelope-from das@FreeBSD.org) Received: from HAL9000.homeunix.com (localhost [127.0.0.1]) by HAL9000.homeunix.com (8.12.9/8.12.5) with ESMTP id h3J0Zx9E012929; Fri, 18 Apr 2003 17:35:59 -0700 (PDT) (envelope-from das@FreeBSD.org) Received: (from das@localhost) by HAL9000.homeunix.com (8.12.9/8.12.5/Submit) id h3J0Zwnj012928; Fri, 18 Apr 2003 17:35:58 -0700 (PDT) (envelope-from das@FreeBSD.org) Date: Fri, 18 Apr 2003 17:35:58 -0700 From: David Schultz To: Fred Clift Message-ID: <20030419003558.GA12856@HAL9000.homeunix.com> Mail-Followup-To: Fred Clift , freebsd-fs@FreeBSD.org, freebsd-stable@FreeBSD.org References: <20030418124914.GA10979@HAL9000.homeunix.com> <20030418101259.M49571-100000@vespa.dmz.orem.verio.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030418101259.M49571-100000@vespa.dmz.orem.verio.net> cc: freebsd-fs@FreeBSD.org cc: freebsd-stable@FreeBSD.org Subject: Re: PATCH: Forcible delaying of UFS (soft)updates X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 19 Apr 2003 00:36:06 -0000 On Fri, Apr 18, 2003, Fred Clift wrote: > There have been many objections about various databases not getting > updates, qmail/sendmail loosing mail, vi removing/overwirting a file, etc, > but aparently these are not the cases for which this patch was designed. > If a person cared about these possiblities, he wouldn't turn this > functionality on. > > If on the other hand, a person were stuck at the doctor's office waiting > room, with low battery, playing nethack, then perhaps this patch is just > what you want. If you're in the doctor's office writing a long letter, and following a crash you find that not only the latest changes but the *entire* *file* just vanished, you might not be such a happy camper. If you leave fsync() alone, your computer will do exactly what you want it to do. It will guarantee that *some* version of the file is on disk, and when you tell your editor to save, it will guarantee that the *latest* version is on disk. So if you want the disk to stay in power save mode, you just don't ask your editor to write it to disk. If you're playing nethack, on the other hand, you won't be fsyncing anyway because nethack doesn't have state that's vitally important.