Considering a Maremma Sheepdog or Livestock Guardian dog ?
Here are some helpful links to answer some of your questions. A LGD is not for everyone, they need room to move preferably acreage, ideally they should have stock (sheep, goats, chickens or other) to bond with, they are much more at home with a job to do feeding their natural instincts. These dogs are extremely protective of their area & companions. A strong dog that at times can be fearless. Unfortunately many of these dogs do bark, generally due to a threat in their area.
Please research your chosen breed before committing or taking one home, beware of any 'mixed breeding' of these dogs. Thousands of years of selected breeding has taken place to produce this wonderful flock guardian, mixed/cross breeding can lead to genetic & health problems.