From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 3 Nov 2002 14:08:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 3 Nov 2002 14:08:22 -0500 Received: from vladimir.pegasys.ws ([64.220.160.58]:22291 "HELO vladimir.pegasys.ws") by vger.kernel.org with SMTP id ; Sun, 3 Nov 2002 14:08:21 -0500 Date: Sun, 3 Nov 2002 11:14:44 -0800 From: jw schultz To: linux-kernel@vger.kernel.org Subject: Re: [lkcd-general] Re: What's left over. Message-ID: <20021103191444.GA18238@pegasys.ws> Mail-Followup-To: jw schultz , linux-kernel@vger.kernel.org References: <20021103170823.10591.qmail@science.horizon.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20021103170823.10591.qmail@science.horizon.com> User-Agent: Mutt/1.3.27i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 03, 2002 at 05:08:23PM -0000, linux@horizon.com wrote: > Just to complicate things, consider this setup: > > # cat /proc/swaps > Filename Type Size Used Priority > /dev/md5 partition 999864 16904 0 > /dev/md6 partition 999864 16924 0 > /dev/md7 partition 999864 16920 0 > > Those are all RAID-1 mirrors, a measure whose ass-saving value I have > enjoyed. > > While a crash dump to just half of one of those mirrors is fine, finding it > might be a little bit tricky. And the fact that the kernel reassembles > the mirrors automatically on boot might make retrieving the data a little > bit tricky, too. > > (After a crash, the mirrors will be inconsistent, so one will get copied > over the other, but I'm not too clear on which direction it'll happen in.) > > I can't NOT reassemble at least some mirrors on boot because / is mirrored! > > Now, to that, add the case that each of those is significantly smaller than > main memory. (2/3 size would still allow swap = 2*ram.) You would want a dump2disk that could span devices. Probably a module that would put a header on each part with a dumpID and sequence#. Compression would also help here as well. The right compression would actually accelerate the process. Early userspace would locate and assemble the pieces and put the dump somewhere. This might happen between mounting / and assembling the other mirrors. That would be up to you. -- ________________________________________________________________ J.W. Schultz Pegasystems Technologies email address: jw@pegasys.ws Remember Cernan and Schmitt