Heh. A convex edge (Fallkniven H1) I'm finding is actually very easy to maintain by hand with a flat sharpener, so long as you don't mind it looking chewed up. I assume a rod works just as well though I haven't tried it on my knife because I haven't got that kind of sharpener. Mirror finishes are nice, but for practical cutting performance they are not necessary. In a SHTF scenario, sharpening your knife by hand using your knee as a work surface is completely plausible, and you're probably going to end up with some flavor of ugly-looking convex anyway.