Oracle Database 12c Backup and Recovery Survival Guide by unknow

Author:unknow
Language: eng
Format: epub
Publisher: Packt Publishing

Note

FRA can't be configured on the tape drive and must be configured on the disk itself. Also, don't set the parameter value of DB_RECOVERY_FILE_DEST to match the value of either DB_CREATE_FILE_DEST or DB_CREATE_FILE_DEST_N. If you do so, a warning will appear in the alert log.

As FRA is the default location for all the backups, the archived redo logs' space usage would be constantly high. Since it's not possible to keep on adding space, it is important to take some proactive measures so that the FRA space isn't completely exhausted. If this happens, not only will the backup jobs start to fail but the database may also hang while performing a redo log switch due to unavailability of space to store the resulting archived redo logs. In order to ensure that the space within FRA will be re-used for new files, you may want to push the backups from it to a tape drive more often. Or, you may use FRA for storing the archived redo logs and schedule the backups directly over tape. If you have a large, frequently changing database, you can implement incremental backups as they will consume less space. If flashback logs are enabled, choose a smaller value for the retention period so that they won't be kept for a longer duration in FRA than needed. Last but certainly not least, implement a retention policy for your backups so that they are marked as obsolete and become candidates for deletion to free up space in FRA.

In order to monitor FRA through SQLPLUS, you can use two views. The first is V$RECOVERY_AREA_USAGE (previously known as V$FLASH_RECOVERY_AREA_USAGE), which will show the space consumption in FRA based on the types of file, the total number of each type of file and so on. The second view, V$RECOVERY_AREA_DEST will show the current location of FRA, the available space quota, used space, and reclaimable space, along with the number of files. The following is an example using the view V$RECOVERY_AREA_DEST:

SQL> SELECT NAME, TO_CHAR(SPACE_LIMIT, '999,999,999,999') AS SPACE_LIMIT, TO_CHAR(SPACE_LIMIT - SPACE_USED + SPACE_RECLAIMABLE, '999,999,999,999') AS SPACE_AVAILABLE, ROUND((SPACE_USED - SPACE_RECLAIMABLE)/SPACE_LIMIT * 100, 1) AS PERCENT_FULL FROM V$RECOVERY_FILE_DEST; 2 3 4 5 6 7 8 NAME ---------------------------------------------------------------------------- ---- SPACE_LIMIT SPACE_AVAILABLE PERCENT_FULL ---------------- ---------------- ------------ /u01/app/oracle/fast_recovery_area 5,033,164,800 4,122,766,848 18.1

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