4. Briefly describe why you need to archived redo log files?
process of turning online redo log files into archived redo log files is called archiving. This process is only possible if the database is running in ARCHIVE LOG mode. You can choose automatic or manual archiving.An archived redo log file is a copy of one of the identical filled members of an online redo log group. It includes the redo entries present in the identical member of a redo log group andalso preserves the group's unique log sequence number. For example, if you are multiplexing your online redo log, and if Group 1 contains member filesa_log1 and b_log1, then the archiver process (ARCn) will archive one of these identical members.You can use archived redo logs to:Recover a databaseUpdate a standby databaseGain information about the history of a database using the LogMiner utilityTo switch a database's archiving mode, use the ALTER DATABASE statement with theARCHIVELOG or NOARCHIVELOG option. The following steps switch a database's archiving mode from NOARCHIVELOG toARCHIVELOG:1.Shut down the database instance.SHUTDOWNAn open database must first be closed and any associated instances shut down before you canswitch the database's archiving mode. You cannot disable archiving if any datafiles need media recovery.2. Back up the database.Before making any major change to a database, always back up the database to protect against any problems. This will be your final backup of the database in NOARCHIVELOG
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- Spring '16
- Oracle Database, Redo log, log file, Tablespace