For reasons I won't go into here, I increased the capacity of an iSCSI LUN to make more room in a handful of logical volumes. Awkwardly, the parent volume group lost its goddamn mind.
I can't recall if I've ever run into this specific scenario or not before, but I doubt it because I rarely mess around with SAN. Well, until recently anyway. Suffice it to say I was stuck until I could find away to dynamically resize the volume group. Turns out you have to use pvresize as in:
I cannot remember now if I had activated or deactivated the vg prior to doing so, but at any rate it worked.