I am very intersted in  geneology also.  The origin seems Teutonic, dear, and its meaning an occupational name for a man who worked in a cellar--- we see this name in Ireland as well because it is common.  It means quite literally man of the cellar or cellar man.    When I look on the internet, it seems this name began as an occupational name for the overseer of the stores, accounts, or household in general as for a monastery or even a castle. Kellers were important as trusted stewards in a great household, and in some cases were promoted to ministerial rank. And I hope this helps you.  And if you have nay more names, I hope I can help you with them.