I actually want a central server, because the main thing I'm worried about is a fire or flood taking out both my computers at once, in which case the sync to a

I actually want a central server, because the main thing I'm worried about is a fire or flood taking out both my computers at once, in which case the sync to a central server works as a backup. (I don't have proper backups beyond Dropbox, because I'm pretty happy for stuff I've actually deleted to stay deleted. Just, in case of a hard drive failure or something similar, I can sync back from Dropbox. That's all I feel I need. Maybe there's something better?)