Entropy is a nasty result of the second law of thermodynamics. Basically, entropy describes the tendency of an ordered system to become disordered, the result of which is the requirement to maintain that system. RMAN is no different. When using RMAN, you have to maintain a number of things to keep it running smoothly.
In this chapter, we talk all about maintaining RMAN. From the crosscheck command to retention policies to redundancy policies, everything you need to know about keeping RMAN from falling apart is provided here. After we have talked about RMAN maintenance issues, we will discuss some issues specific to the recovery catalog, including an introduction to the recovery catalog schema itself.