The redo log, also referred to as the transaction log, is a datafile that contains all transactions and updates that occur to an application database. Normally, data is de-staged from memory into the redo log for performance reasons. Oracle switches redo logs when one fills up. Possibilities include problems related to the application itself or the disk hardware on which the datafiles reside. Last, there is the control file that contains information Oracle needs to start a database.
Most installations have two or more control files for critical databases.
The files should reside on RAID devices or separate disk hardware devices. Native Oracle Backup and Recovery Overview Oracle provides several utilities that facilitate the backup and recovery of Oracle objects. The two types of backups can be categorized as either physical backups or logical backups. The table mode export processes specific tables. The user mode export is used to export all of a user's objects.