Recording here for posterity:
Problem:
runaway process, logs full, hard drive full
some dominions games will not restart
Något gick fel!
getmany failed
Answer:
Move last 2h file from game directory and try again.
LongerAnswer:
It turns out that during the problem someone did a turn. The last 2h received was a zero byte file. Removing it fixed the problem. It might also be worth trying anytime the game wont restart. Move the last 2h you received and try it then.
Tip:
Its also always a good idea to use the wonderful --preexec switch to run some routine (script or bat file) for zippng the files just before each hosting to provide backups you can restore from. Using the --postexec to do another save immediately after each hosting might not be a bad idea either.
yes I know that this seems head-slappingly obvious NOW but it caused me a sleepless night until I figured it out so I dont care if it makes me look bad to post this. It might help someone else later