I know there are a few lvm2 experts lurking here :) I have a 500gig disk that is split roughly in half between two volume groups, each containing four physical volumes, and each vg is formatted into an ext4 filesystem of roughly 250GB.
What I plan to do is merge the two volume groups into one, containing one big ext4 filesystem, which will contain all of the files currently on the disk. Can this be done without copying one of the existing ext4 filesystems to a separate drive first, and then copying it back after extending the remaining vg/filesystem? (One filesystem has 24GB free and the other has 25GB free.) I'm expecting a "no" but I'd like to be wrong :)