From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <521C814E.1050908@redhat.com> Date: Tue, 27 Aug 2013 12:37:02 +0200 From: Zdenek Kabelac MIME-Version: 1.0 References: In-Reply-To: Content-Transfer-Encoding: 7bit Subject: Re: [linux-lvm] Duplicate physical volumes Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: LVM general discussion and development Cc: oliver_block2@web.de Dne 25.8.2013 13:28, oliver_block2@web.de napsal(a): > Dear LVM list, > this is my first posting to this list and actually I am making my first > experiences with LVM. The following is my situation: > I had a RAID 1 consisting of /dev/sdb1 and /dev/sdc1 making /dev/md2 and used > this device as a physical volume for LVM. I used this inside the volume group > vg_data. > Now I decided to convert this RAID 1 into a RAID 5 by "adding a third and > identical partition /dev/sdd1". It follows how I am going to realize this: > First I removed /dev/sdc1 from /dev/md2 (the old RAID 1) leaving it in > degraded state. > Then I created a new RAID 5, having device name /dev/md0 with a total of three > disks, but running only with two disks for the moment, namely /dev/sdc1 and > /dev/sdd1. > The plan is now to initialize /dev/md0 as a physical volume and add a volume > group and logical volume on top of this. Then I would copy the data from the > old RAID 1 to the new RAID 5. Finally I will remove the old RAID 1 and add the > remaining device /dev/sdb1 to the new RAID 5. Then the conversion would be > complete. > Now the actual problem related to LVM: You need to make sure you have proper filter rules set in lvm.conf. > While trying to initialize the new /dev/md0 as a pysical volume for LVM, I get > the following message: > # pvcreate /dev/md0 > Incorrect metadata area header checksum on /dev/md0 at offset 3000456183808 > Found duplicate PV LNqPKpqdtqcLkmiqHYOeeVddNYx7FDOq: using /dev/md2 not > /dev/md0 > Can't initialize physical volume "/dev/md0" of volume group "vg_data" > without -ff When you are destroying previous raids - you should properly wipe disk headers. Otherwise you need to use force options to overwrite existing one, with the risk you could do more damage if you are not 100% what you are doing. Zdenek