Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 25 Nov 2001 22:35:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 25 Nov 2001 22:35:42 -0500 Received: from vasquez.zip.com.au ([203.12.97.41]:12812 "EHLO vasquez.zip.com.au") by vger.kernel.org with ESMTP id ; Sun, 25 Nov 2001 22:35:34 -0500 Message-ID: <3C01B845.33314F49@zip.com.au> Date: Sun, 25 Nov 2001 19:34:29 -0800 From: Andrew Morton X-Mailer: Mozilla 4.77 [en] (X11; U; Linux 2.4.14-pre8 i686) X-Accept-Language: en MIME-Version: 1.0 To: Oliver Xymoron CC: linux-kernel Subject: Re: ext3: kjournald and spun-down disks In-Reply-To: <3BFF06CA.71B99D3C@zip.com.au> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Oliver Xymoron wrote: > > Ok, so what's the theory behind the journal timer? Why would we want > ext3 journal flushed more or less often than ext2 metadata given that > they're of equivalent importance? umm, err.. If your machine crashes, ext3 will restore its state to that which pertained between zero and five seconds before the crash. With ext2+fsck, things are not as clear. Your data will be restored to that which pertained from zero to thirty seconds prior to crash. inodes and superblock to that which pertained from zero to thirty five seconds before the crash, stuff like that. A five second window is short enough for you to be confident that everything you want is still there. With thirty seconds, uncertainty creeps in. Yes, it needs to be configurable. - - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/