Bear Spray or Bear Deterrent is your best chance to survive a bear attack while in bear country. It is important to have the Bear Spray accessible and in close reach. Having a holster is an ideal and safe way to carry your bear spray so it's not buried in your backpack.
Please be aware that although bear deterrents are very successful at stopping aggressive bear behaviour, they cannot guarantee 100% effectiveness. Precaution and good bear practices should always be taken when in bear country.