From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [172.16.45.118] (dhcp-118.brisbane.redhat.com [172.16.45.118]) by pobox.brisbane.redhat.com (8.13.1/8.13.1) with ESMTP id m048If2G014875 for ; Fri, 4 Jan 2008 18:18:41 +1000 Message-ID: <477DEB7B.7050100@gmail.com> Date: Fri, 04 Jan 2008 18:16:59 +1000 From: David Robinson MIME-Version: 1.0 Subject: Re: [linux-lvm] How to 'copy' a volume? References: <477D7E55.3050003@soe.ucsc.edu> In-Reply-To: <477D7E55.3050003@soe.ucsc.edu> Content-Transfer-Encoding: 7bit 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 Erich Weiler wrote: > Greetings all- > > I have a problem I'm trying to solve, was hoping someone would know how > to get around it... > > I have a 2TB volume group, and one 500GB volume in it. There is a Xen > VM in that volume group. What I'd like to do is 'copy' the volume and > name it something else so I can use it as a 'template' for other VMs. > > I know that LVM has the 'snapshot' capability. But this doesn't look > like it's what I need, as I don't want my duplicate volume to have any > affiliation with the original at all. I actually want to duplicate VM > to take up just as much space as the first and be completely independent > of any changes on the first. Is there a way of achieving this? Could I > maybe simply make sure the volume is unmounted and not in use, then copy > the /dev/mapper/myvolume file to something else? I bet it's more > involved than that... :) I find 'dd' is the simplest way of doing this. Unmount the volume, create a new logical volume of equal or greater size, then 'dd' from one to the other: lvcreate -L 500G -n clone volgroup00 dd if=/dev/volgroup00/original of=/dev/volgroup/clone Rather than copying VMs I snapshot them. I create a template system, create a snapshot of it, then modify the VMs config so it uses the snapshot as its disk (so the original is unmodified). If I need another copy of the VM its only a matter of creating another snapshot of the template LV, then copying and modifying the config. I usually set the extent size low so that modifications within the VMs don't chew up lots of space too. --Dave