In a large saucepan set over medium-high heat, bring the water, milk and salt to a boil.Add the oats and raisins and stir well. Bring back to the boil and then reduce the heat to low. Cover and simmer for 25 to 30 minutes, stirring every 5 minutes or so and scraping the bottom of the pan well each time to prevent the oatmeal from attaching.Once the oats are tender and the liquid has practically completely evaporated, stir in the vanilla and cinnamon, kill the heat, put the lid back on and let the oatmeal sit for about 10 minutes, or until it has reached the desired thickness.Serve immediatelyLeftovers can be refrigerated for up to one week and may be consumed cold or slightly reheated. To reheat, stir in a little bit of water or milk and reheat over low heat in a small saucepan or in the microwave.