Businesses buy IT resources because they need them for their applications to perform. When applications are not performing, businesses are not running. However, when deciding how many resources to buy, IT professionals face a challenge. What type of resources do I buy, and how much? The often-unpredictable nature of application demand makes it impossible to understand exactly how many resources are needed at any given second, so businesses allocate more resources than they think will be necessary, hoping they will have so much supply that there will not be any points of congestion or resource shortages.