From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 1 Oct 2001 08:11:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 1 Oct 2001 08:11:16 -0400 Received: from tele-2.inweb.net.uk ([212.38.64.10]:10505 "EHLO tele2.inweb.co.uk") by vger.kernel.org with ESMTP id ; Mon, 1 Oct 2001 08:11:01 -0400 Message-ID: <00c401c14a71$f8c478f0$1e1cd2d5@chris> From: "Chris Andrews" To: Subject: Re: RAID5: mkraid --force /dev/md0 doesn't work properly Date: Mon, 1 Oct 2001 13:09:50 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4807.1700 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4807.1700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Evan Harris (eharris@puremagic.com) said: > I have a 6 disk RAID5 scsi array that had one disk go offline through a > dying power supply, taking the array into degraded mode, and then another > went offline a couple of hours later from what I think was a loose cable. I had much the same happen, except that I lost 6 disks out of 12 (power failure to one external rack of two), so I had no chance of starting in degraded mode. In this situation, where there are not enough disks for a viable raid, what is the recommended solution? In my case, there was nothing wrong with the six disks, but their superblock event counters were out of step. Is the best idea to modify /etc/raidtab as discussed, and run mkraid with the real force option? What I actually did was to hand-edit the superblocks on the disks, and got the array going. That experience would lead me to suggest that there's room for some more options to allow the use of disks where there's actually nothing wrong, but right now the raid code won't use them. I'm thinking of a set of '--ignore' options to raidstart: --ignore-eventcounter, --ignore-failedflag, etc, which an admin could use as an alternative to trying mkraid. Right now it seems that software-raid works well, until it doesn't, at which point you're stuck - there's very little in the way of tools or overrides to sort problems out. Something other than 'try mkraid force as a last resort' would be useful. (If anyone thinks this is a good idea, yes, I am volunteering to provide patches...) Chris.