Design and Execution Transparency

Both refers to the freedom from knowing how the distributed database is designed and where a transaction executes.

Reliability is defined as the probability that a system is running (not down) at a certain point.

Availability is defined as the probability that a system is continuously available during a time interval.

To construct a system that is reliable,we can adopt several approaches.

1.Fault tolerance: it recognizes that faults will occur,and it designs mechanisms that can detect and remove faults before they can result in a system failure.

2.To ensure that the final system doesnot contain any faults.

This is done through an exhaustive design process followed by extensive quality control and testing.