From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: Re: split RAID1 during backups? Date: Mon, 24 Oct 2005 15:37:58 +0400 Message-ID: <435CC796.4000207@wasp.net.au> References: 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: Jeff Breidenbach Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Jeff Breidenbach wrote: > So - I'm thinking of the following backup scenario. First, remount > /dev/md0 readonly just to be safe. Then mount the two component > paritions (sdc1, sdd1) readonly. Tell the webserver to work from one > component partition, and tell the backup process to work from the > other component partition. Once the backup is complete, point the > webserver back at /dev/md0, unmount the component partitions, then > switch read-write mode back on. Why not do something like this ? mount -o remount,ro /dev/md0 /web mdadm --fail /dev/md0 /dev/sdd1 mdadm --remove /dev/md0 /dev/sdd1 mount -o ro /dev/sdd1 /target umount /target mdadm -add /dev/md0 /dev/sdd1 mount -o remount,rw /dev/md0 /web That way the web server continues to run from the md.. However you will endure a rebuild on md0 when you re-add the disk, but given everything is mounted read-only, you should not practically be doing anything and if you fail a disk during the rebuild the other disk will still be intact. I second jurriaan's vote for rsync also, but I would be inclined just to let it loose on the whole disk rather than break it up into parts.. but then I have heaps of ram too.. Regards, Brad -- "Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." -- Douglas Adams