You may not have very suitable types of wood available to you for self-sustaining open fires, although they usually do OK in a stove. If you keep the logs close (a little experimenting will be useful), it's not too hard to keep active coals eating their way through the logs (have to tend the fire to keep them close but still allow air in) - it's smoky and not a picture perfect cheery snapping fire, but it has worked for me farther North than you are.

Even down here in the northern hardwood forests there are many woods that won't burn nicely in large short sections on an open fire - split or whole. An ample supply of wrist-size splits and/or dead limbs is a better bet for open fires with less enthusiastic types of wood. Yeah, you have to wake up once in a while to toss a few more on the fire, but that's no hardship as far as I'm concerned.

Down here I can readily build a fire that holds itself well overnight, but I have a much better selection of wood to use. With the woods I believe you have available, it seems to take a honkin huge fire to build that sustaining pile of coals and ashes and wood.

I doubt that there is anything wrong with your techique - it's probably a function of the wood you have to work with. Outdoorsmen in your area probably can better answer your question than I can.

HTH,

Tom