From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 1 May 2001 17:21:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 1 May 2001 17:21:36 -0400 Received: from router-100M.swansea.linux.org.uk ([194.168.151.17]:5900 "EHLO the-village.bc.nu") by vger.kernel.org with ESMTP id ; Tue, 1 May 2001 17:21:21 -0400 Subject: Re: Linux Cluster using shared scsi To: Eric.Ayers@intec-telecom-systems.com Date: Tue, 1 May 2001 22:24:45 +0100 (BST) Cc: alan@lxorguk.ukuu.org.uk (Alan Cox), dledford@redhat.com (Doug Ledford), James.Bottomley@steeleye.com (James Bottomley), Chris.Roets@compaq.com (Roets Chris), linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org In-Reply-To: <15087.9645.153829.265882@gargle.gargle.HOWL> from "Eric Z. Ayers" at May 01, 2001 05:07:57 PM X-Mailer: ELM [version 2.5 PL1] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: From: Alan Cox Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > reserved. But if you did such a hot swap you would have "bigger > fish to fry" in a HA application... I mean, none of your data would be > there! You need to realise this has happened and do the right thing. Since it could be an md raid array the hotswap is not fatal. If its fatal you need to realise promptly before you either damage the disk contents inserted in error (if possible) and so the HA system can take countermeasures > if the kernel (by this I mean the scsi midlayer) was maintaining > reservations, that there would be some logic activated to "handle" > this problem, whether it be re-reserving the device, or the ability to Suppose the cluster nodes don't agree on the reservation table ? > Bus resets in the Linux drivers also tend to happen frequently when a > disk is failing, which has tended to leave the system in a somewhat > functional but often an unusable state, (but that's a different story...) The new scsi EH code in 2.4 for the drivers that use it is a lot better. Real problem.