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Backup - Archival Backups

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Backup - Archival Backups
- Archival Backups
- Lab: Creating an Archival Backup

Archival Backups

Problem:
- to simply keep the specific backup (and what is necessary to keep it consistent and recoverable) for a specified amount of time, e.g., for two years, and to maintain a retention policy 长期保留备份的同时不改变留存政策
archival backup:
- a snapshot of the database at a point in time that can be used, for example, to restore the database to another host, for testing purposes.
- a backup that is not under your normal retention policies
  - a marker on backup that overrides any configured retention policy
  - either considered obsolete only after a specific time that you specify
  - or never considered obsolete.
    - need to use a recovery catalog.
- can be created with an open or a mounted database.

diagram_archival_backup

Prerequisite:
- use a recovery catalog for an OPEN database.
- not use a recovery catalog: database in MOUNTED state.
Characteristics:
- Archival backups cannot be written to the fast recovery area.
  - So if you have one, you must provide a FORMAT clause to specify a different location.
- An archival backup also guarantees that all of the files needed to restore the backup are included.
  - Including:
    - data files
    - SPFILE
    - archived log files (only those needed to recover an online backup)
    - the relevant autobackup files.
  - All these files must go to the same media family (or group of tapes).
- The only redo logs that are kept are those required to restore this backup to a consistent state.
- An archival backup is retained for as long as specified. Even if you have a much smaller retention window and run the DELETE OBSOLETE command, the archival backup remains.不会被删除直到指定时间

Syntax:

BACKUP ... KEEP {FOREVER|UNTIL TIME 'SYSDATE + <n>'} RESTORE POINT <restore_point_name>

-- Example
KEEP {FOREVER | UNTIL TIME [=] ' date_string '}
NOKEEP
[RESTORE POINT rsname]

-- List all restore points known to the RMAN repository:
LIST RESTORE POINT ALL;

-- Display a specific restore point:
LIST RESTORE POINT 'rsname';

-- -------- Managing Archival Database Backups
-- Archiving a database backup forever:
CONNECT CATALOG rman/rman@catdb  -- required catalog
CHANGE BACKUP TAG 'consistent_db_bkup' KEEP FOREVER;

-- Changing the status of a database copy:
-- to make a backup that is currently exempt from the retention policy eligible for the OBSOLETE status.
-- applies to all backups of the type specified if tag is not specified.
CHANGE COPY OF DATABASE CONTROLFILE NOKEEP;

UNTIL TIME clause: 标明备份保留时间
- enables you to specify when the archival backup is no longer immune to the retention policy.
FOREVER:
- the backup is an archival backup until you take some other action to change that.
RESTORE POINT clause:标明数据对齐的时间点
- to specify the name of a restore point to be associated with this backup.
  - creates a consistency point in the control file.
  - assigns a name to a specific SCN.
    - The SCN is captured just after the data file backup completes.
- The archival backup can be** restored and recovered for this point in time, enabling the database to be **opened.
- In contrast, the UNTIL TIME clause specifies the date until which the backup must be kept.
- not valid with the CHANGE command,
  - because there is no way to create the restore point for a time that has already passed (when the backup was created).一旦生成, 无法更改

Lab: Creating an Archival Backup

-- mount db
SHUTDOWN IMMEDIATE;
STARTUP MOUNT;

-- to make an archival backup of your ORCLCDE database with the KEEP FOREVER option
BACKUP AS COPY DATABASE KEEP FOREVER;
-- It failed because a backup with the KEEP FOREVER option requires the use of a recovery catalog.
-- A recovery catalog is required when KEEP FOREVER is specified because backup records will eventually age out of the control file.

lab_archival_backup

-- to make an archival backup of your ORCLCDE database that will be kept for 9 days.
BACKUP AS COPY DATABASE KEEP UNTIL TIME 'SYSDATE+9';
-- It failed because a backup with the KEEP option (an archival backup) cannot be written to the Fast Recovery Area.
-- Allowing this has the potential of causing the Fast Recovery Area to quickly run out of space.

lab_archival_backup

-- create dir: /home/oracle/archival_backup/
-- Create an archival backup with a FORMAT clause that will direct RMAN to create the backup in the /home/oracle/backup directory and keep it for 9 days.
BACKUP DATABASE FORMAT '/home/oracle/archival_backup/%U' TAG keep_db_tag KEEP UNTIL TIME 'SYSDATE+9';

lab_archival_backup

ALTER DATABASE open;

LIST BACKUP;

-- delete obsolete backup in FRA
DELETE OBSOLETE;

lab_archival_backup

Confirm the archival backup will not be removed

ls /home/oracle/archival_backup/

lab_archival_backup

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