From mboxrd@z Thu Jan 1 00:00:00 1970 From: Norman Schmidt Subject: Re: split RAID1 during backups? Date: Tue, 25 Oct 2005 10:35:53 +0200 Message-ID: <435DEE69.8030605@naa.net> References: Reply-To: schmidt@naa.net Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Jeff Breidenbach schrieb: > Ok... thanks everyone! Something from me: What you should be able to do with software raid1 is the following: Stop the raid, mount both underlying devices instead of the raid device, but of course READ ONLY. Both contain the complete data and filesystem, and in addition to that the md superblock at the end. Both should be identical copies of that. Thus, you do not have to resync afterwards. You then can backup the one disk while serving the web server from the other. When you are done, unmount, assemble the raid, mount it and go on. Eg. /dev/md1 consists of /dev/hda5 and /dev/hdc5 and has a working fs on it. /dev/md1 is mounted on /data. umount /dev/md1 mdadm -S /dev/md1 mount -r /dev/hda5 /data mount -r /dev/hdc5 /backup do your backup umount /dev/hda5 umount /dev/hdc5 mdadm -A /dev/md1 mount /dev/md1 /data Please could somebody double-check or confirm this first? Hope this helps, Norman. -- Norman Schmidt Institut fuer Physikal. u. Theoret. Chemie Dipl.-Chem. Univ. Friedrich-Alexander-Universitaet schmidt@naa.net Erlangen-Nuernberg +49 9131 852 7321 IT-Systembetreuer Physikalische Chemie