Place white beans in large pot full of cold water. Bring to a boil; drain.
Cover beans again with cold water and bring to a boil. Add the bacon and sausage and simmer very slowly over low heat for one hour.
Heat the olive oil in a separate pan and add the onion. Cook 2-3 minutes and then add the garlic. Mix together and remove to a flameproof casserole. Add the white beans drained, the bacon, salt, pepper and 1/4 cup water. Cook very slowly until the beans are done, as long as two hours, depending on the beans.