Oracle Database 11 g - Online Public Access Catalog

288 CHAPTER 6 ■ BACKUP AND RECOVERY/u01/aapp/oracle/arch1 directory and the redo log 100 from the second archived redo log location,/u01/app/oracle/arch2.Backup ShreddingOracle Database 11g lets you render encrypted backups inaccessible by destroying the encryptionkey of the backup. You don’t need to physically access the backup media to perform thistask, also called backup shredding. Backup shredding is disabled by default. Here’s how youconfigure backup shredding:RMAN> configure encryption external key storage on;Alternatively, you can use the set encryption command as shown here to configurebackup shredding:RMAN> set encryption external key storage on;To actually use the backup shredding feature, you must use the delete force command,as shown here:RMAN> delete force backup;using target database control file instead of recovery catalogallocated channel: ORA_DISK_1channel ORA_DISK_1: SID=153 device type=DISKRMAN>Note that you can’t shred RMAN backups protected with a password.Optimized Backing Up of Undo DataUp until this release, during a backup, all undo data in the undo tablespace was backed up. Theundo data might include both committed as well as uncommitted data. The committed datathat’s recorded in the undo tablespace doesn’t serve any useful purpose, since that data is alsorecorded in the data blocks upon committing the relevant transactions. In Oracle Database11g, during a backup, the committed data isn’t backed up, thus leading to a saving of storagespace as well as faster backups for large OLTP-type databases.Since the new optimized undo backup is automatically enabled, you don’t have to configureanything special to take advantage of this feature.Active (Network-Based) Database DuplicationPrior to Oracle Database 11g, database duplication through RMAN always meant backup-basedduplication, since the duplicate database relied on the source database’s datafile and archivedredo log backups. In Oracle Database 11g, you can directly duplicate a database over the networkwithout having to back up and provide the source database files. This direct database duplicationis called active database duplication or network-aware database duplication. This is definitelyone of Oracle Database 11g’s more useful innovations, since you can create duplicate databases