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.Performing Backup and Recovery with Recovery Manager 8-13 device_type_list This option can be used to limit the backup setswhich will be considered when deciding whether ornot a file is unrecoverable or is in need of a morerecent backup.If specified, only backup sets whichreside on one of the specified device types will beconsidered.If not specified, all available backup setswill be considered.Datafile copies will always beconsidered.Listing Unrecoverable DatafilesYou can use the report unrecoverable command to list all datafiles that areunrecoverable.A datafile is considered unrecoverable if anUNRECOVERABLE operation has been performed against an object residingin the datafile since the last backup of the datafile.Note that the non-existence of any backup of a datafile is not sufficient reasonto consider it unrecoverable.Such datafiles can be recovered through the useof the create datafile command, provided that logs starting from when the filewas created are still in existence.Example: Datafiles Requiring a New BackupThe following command lists all datafiles that cannot be completely recoveredfrom the existing backups because redo may be missing:report unrecoverable;Listing Datafiles that Need to be Backed Upreport need backup lists all datafiles that are considered to be in need of a newbackup.The report assumes that the most recent backup would be used in theevent of a restore.need_backup_operands are as follows:incremental An integer specifying a threshold number ofincremental backups.If complete recovery of adatafile would require the application of more thanthis many incremental backups, then the datafile isconsidered in need of a new full backup.Thisassumes the most efficient strategy, which is to usethe lowest level of incremental backup wheneverthere is a choice.This is the same strategy that would8-14 Oracle8 Backup and Recovery Guide be used if the file were actually being recovered bythe recover command.Note that files for which no backups exist will notappear in this list.They can be found by using thereport need backup days command.days An integer specifying a threshold number of days oflog files that will need application during recovery ofthis file.For online files, this is the number of dayssince the last full or incremental backup of a file.Thetime of day is not considered when calculating theage of a backup set (i.e.a backup taken anytimeyesterday is 1 day old).If multiple copies of a backupset exist, the completion time of the original backupset is used.If the most recent backup of this file isolder than this number of days, then the file isconsidered to be in need of a new backup.If the target database controlfile is mounted andcurrent, the following optimizations will be made tothis report:1.Files which are offline and whose most recentbackup contains all changes to the file will not beincluded.2.Files which were offline and are now online, andwhose most recent backup contains all changes up tothe offline time, will only be reported if they havebeen online for more than the specified number ofdays.redundancy An integer specifying the minimum level ofredundancy considered necessary.redundancy 2means that there must be at least 2 backups of eachdatafile for it for it to be considered not in need of abackup.Example: Datafiles That Need to be Backed UpThe following command reports all datafiles in the database that wouldrequire the application of three or more incremental backups to be recoveredto their current state:report need backup incremental 3 database;Performing Backup and Recovery with Recovery Manager 8-15 The following command reports all datafiles from tablespace system thathaven t had a backup (full or incremental) in 5 or more days:report need backup days 5 tablespace system;Listing Obsolete Datafile BackupsYou can use the report obsolete command to list backup sets and datafilecopies that can be deleted because they are redundant [ Pobierz całość w formacie PDF ]