Oracle recommends a daily incremental backup strategy. In this backup strategy;<\/p>\n
Day 1: Full backup is taken.<\/p>\n
Day 2: Incremental backup is taken. (Incremental Level 0 Backup)<\/p>\n
Day 3: Incremantal backup is taken. (Incremental Level 1 Backup)
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The incremental backup taken the previous day is combined with the full backup (Level 0 ). This backup is called Incremental Cumulative backup.<\/p>\n
In this backup strategy, the following path is followed in disaster situations.<\/p>\n
When you want to go back to a time before Incremental Backup is taken after a Full backup is taken, Full backup is returned and archive redo logs are run on it.<\/p>\n
After taking the Incremental backup on the 2nd day, if it is desired to return to a time before the Incremental backup on the 3rd day, the incremental level 0 backup on the 2nd day is returned and the archive redo logs are run on it.<\/p>\n
When it is desired to return to a time before Incremental backup is taken on the 3rd day and before the 4th day Incremental backup is taken, archive redo log’ on top of the cumulative backup formed as a result of combining the level 0 incremental backup on the 2nd day with the level 1 incremental backup taken on the 3rd day. are operated.<\/p>\n
The RMAN Script that makes this backup strategy is as follows.<\/p>\n
\tRESYNC CATALOG FROM DB_UNIQUE_NAME ALL;\r\n\tRECOVER COPY OF DATABASE WITH TAG 'dgbkup';\r\n\tBACKUP DEVICE TYPE DISK INCREMENTAL LEVEL 1 FOR RECOVER OF COPY WITH TAG 'dgbkup' DATABASE;\r\n\tBACKUP DEVICE TYPE SBT ARCHIVELOG ALL;\r\n\tBACKUP BACKUPSET ALL;\r\n\tDELETE ARCHIVELOG ALL;\r\n<\/pre>\nHere;<\/p>\n
RESYNC CATALOG FROM DB_UNIQUE_NAME ALL;<\/strong> Before starting to take backup, it connects to all databases and RESYNC the catalog.<\/p>\n
RECOVER COPY OF DATABASE WITH TAG ‘dgbkup’;<\/strong> It processes the Level 1 Incremental Backup taken the previous day over the Level 0 backup. So we have Cumulative backup.<\/p>\n
Day 1: Since we only have Level 0 backup, there will be no merge.<\/p>\n
Day 2: There is a level 0 and level 0 incremental backup in my hand. Again, there is no merging.<\/p>\n
Days 3 and Following: In addition to the backups we have, there is also Level 1 incremental backup. This backup is combined with the Level 0 incremental taken the previous day.<\/p>\n
BACKUP DEVICE TYPE DISK INCREMENTAL LEVEL 1 FOR RECOVER OF COPY WITH TAG ‘dgbkup’ DATABASE;<\/strong> Creates Level 1 Incremental Backup.<\/p>\n
Day 1: Level 0 backup is taken.<\/p>\n
2nd and Subsequent Days: Level 1 incremental backup is taken.<\/p>\n
BACKUP DEVICE TYPE SBT ARCHIVELOG ALL;<\/strong> Takes backup of archive logs to tape.<\/p>\n
BACKUP BACKUPSET ALL;<\/strong> Takes backup of backup sets.<\/p>\n
DELETE ARCHIVELOG ALL;<\/strong> Archive logs are deleted according to the setup specified in CONFIGURE ARCHIVELOG DELETION POLICY.<\/p>\n
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