Scalability and Availability are mentioned so often that often it is difficult to know what they actually mean in each case. They are often interchanged and create confusion that results in poorly managed expectations and unrealistic metrics. This DZone Refcard provides you with the tools to define these terms so that your team can implement mission-critical systems with well-understood performance goals. This Refcard also covers: An Overview of Scalability and High Availability, Implementing Scalable Systems, Caching Strategies, Clustering, Redundancy and Fault Tolerance, Hot Tips, and More.