From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: Re-assembling a software RAID in which device names have changed. Date: Tue, 08 Apr 2008 22:37:34 +0400 Message-ID: <47FBBB6E.8040307@msgid.tls.msk.ru> References: <47FBAA76.20008@msgid.tls.msk.ru> Reply-To: mjt@tls.msk.ru Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: "Sean H." Cc: linux-raid List-Id: linux-raid.ids [Please respect the Reply-To header] Sean H. wrote: [] > My mdadm.conf is configured with UUIDs: Ok. > DEVICE partitions Ok. > ARRAY /dev/md0 level=raid5 num-devices=5 > uuid=58dcdaf3:bdf3f176:f2dd1b6b:f095c127 > Tried the following: 'mdadm --assemble /dev/md0 --uuid > 58dcdaf3:bdf3f176:f2dd1b6b:f095c127' > ... and got this: mdadm: /dev/md0 assembled from 2 drives - not enough > to start the array. > (Which is what I've been getting for a while, now.) Ok. So it's a different problem you have. What's the reason you think it's due to re-numbering/naming of the disks? When you unplugged 3 your disks, I suspect linux noticed that fact and md layer marked them as "failed" in the array, with the 2 still here. Now, when you have all 5 of them again, 2 of them (the ones which were left in the system) are "fresh", and 3 (the ones which were removed) are "old". So you really don't have enough fresh drives to start the array. Now take a look at verbose output of mdadm (see -v option). If my guess is right, use --force option. And take a look at the Fine Manual, after all -- at the section describing assemble mode. > It's possible to correct this issue by unplugging the three drives and > plugging them back in and rebooting, so the drives get their original > /dev/sd* locations, is it not? (Even if it it possible, I'd like to > learn how to fix problems like this at the software level over the > hardware level.) Please answer this question. Why do you think that the array does not start because of disk renumbering? /mjt