Oracle Database 11 g - Online Public Access Catalog

276 CHAPTER 6 ■ BACKUP AND RECOVERYYou can also use the section size clause with the validate datafile command. We’llshow an example of this later in this chapter, when we discuss the new version of the validatecommand.Managing Multisection BackupsThe SECTION_SIZE column in both the V$BACKUP_DATAFILE and RC_BACKUP_DATAFILEviews shows the number of blocks in each section of a multisection backup. Of course, a wholefile backup will show a value of zero in this column. If you haven’t performed any multisectionbackups, the SECTION_SIZE column will have a zero value. The V$BACKUP_SET and RC_BACKUP_SET views tell you which backups are multisection backups. The following example shows aquery on the V$BACKUP_DATAFILE view:SQL> select piece, multi_section from v$backup_datafile;PIECESMUL------- --------1 NO2 YES7 YES4 NOSQL>The query shows that backup pieces 2 and 7 are multisection backups since they each havea value of YES for the column MULTI_SECTION.Creating Archival (Long-Term) BackupsYou can use the backup ... keep command in Oracle Database 11g to retain backups forlonger periods than specified by your retention policy for RMAN backups. Using this command,you can make archival backups that you can retain for years, if you want, for purposes such asmeeting regulatory requirements. You can also use archival backups for periodically restoringa database for testing purposes. These archival backups contain all the files necessary to restoreand recover a database.In Oracle Database 10g, you used the keep option to override any configured retention policyfor a backup. The keep option made the backup exempt from a retention policy for a specifiedperiod of time. The keep forever option (requires a recovery catalog) specified that a backupor copy never expired. In Oracle Database 11g, you use the keep and keep forever options toessentially do the same thing as before. However, some of the options from the previous releasearen’t used now, and there is a new option called restore point. Since the backup ... keepcommand is at the heart of the archival backups feature, we’ll cover this command in moredetail in the following sections.The backup … keep Command in Oracle Database 10gBefore Oracle Database 11g, the backup ... keep command had the following options: