Media recovery is a process to recover database from backup when physical disk failure occur.,in other way loss of physical file which has to be taken care by Oracle DBA
Media failures fall into two general categories: permanent and temporary.
Permanent media failures are serious hardware problems that cause permanent loss of data on the disk. Lost data cannot be recovered except by repairing or replacing the failed storage device and restoring backups of the files stored on the damaged storage device.
Temporary media failures are hardware problems that make data temporarily inaccessible, but do not corrupt the data. Following are two examples of temporary media failures:
- A disk controller fails. Once the disk controller is replaced, Oracle can access the data on the disk.
- Power to a storage device is cut off. Once the power is returned, the storage device and all associated data is accessible again.