I have a series of unmounted lv's that are used in xen vm's of various flavors in a lab environment. I made a script that I use to backup all of them prior to doing anything I may need to undo and all I execute is:

dd if=/dev/vgname/lvname of=/dir/name.img

Are there any additional parameters I should use? I haven't tried to restore this into an lv, but I did swap the 'phy' specification for 'file' and started a vm using the backed up image and it was fine.

Thanks! jlc