Backup Optimization for SBT Backups With Redundancy Retention Policy

ocp 053

703. Given below are RMAN commands to enable ba ckup optimization and set  the retention policy:

 

The USERS tablespace has never been backed up. Y ou take the USERS tablespace offline on Monday.

View the Exhibit to examine the operations performed by using RMAN. Which two statements are true

about the backup of the USERS tablespace? (Choose two.)

 

A.It will be backed up as a part of database backup on Friday.  

B.It will be backed up as a part of database backup on Tuesday.  

C.It will not be backed up as a part of database backup on Wednesday.  

D.The command on Sunday deletes the backup of the USERS tablespace taken on Tuesday.

Answer: AB 

答案解析：

从以下答案指导BD正确。

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmconfb.htm#BRADV89464

Backup Optimization for SBT Backups With Redundancy Retention Policy

Assume that you configure a retention policy for redundancy. In this case, RMAN only skips backups of offline or read-only data files to SBT when there are r + 1 backups of the files, where r is set in CONFIGURE RETENTION POLICY TO REDUNDANCY r.

For example, assume that you enable backup optimization and set the following retention policy:

CONFIGURE DEFAULT DEVICE TYPE TO sbt;

CONFIGURE BACKUP OPTIMIZATION ON;

CONFIGURE RETENTION POLICY TO REDUNDANCY 2;

With these settings, RMAN only skips backups when three identical files are already backed up. Also assume that you have never backed up the userstablespace, which is read/write, and that you perform the actions described in Table 5-5 over the course of the week.

Table 5-5 Effect of Redundancy Setting on Backup Optimization

Day	Action	Result	Redundant Backup
Monday	Take users offline normal.
Tuesday	BACKUP DATABASE	The users tablespace is backed up.
Wednesday	BACKUP DATABASE	The users tablespace is backed up.
Thursday	BACKUP DATABASE	The users tablespace is backed up.	Tuesday backup
Friday	BACKUP DATABASE	The users tablespace is not backed up.	Tuesday backup
Saturday	BACKUP DATABASE	The users tablespace is not backed up.	Tuesday backup
Sunday	DELETE OBSOLETE	The Tuesday backup is deleted.
Monday	BACKUP DATABASE	The users tablespace is backed up.	Wednesday backup

The backups on Tuesday, Wednesday, and Thursday back up the offline users tablespace to satisfy the condition that three backups must exist (one more than redundancy setting). The Friday and Saturday backups do not back up the users tablespace because of backup optimization. The Tuesday backup of users is obsolete beginning on Thursday.

On Sunday, you delete all obsolete backups, which removes the Tuesday backup of users. The Tuesday backup is obsolete because of the retention policy setting. The whole database backup on Monday then backs up the users tablespace to satisfy the condition that three backups must exist (one more than redundancy setting). In this way, you can recycle your tapes over time.

 

RMAN> show all;

RMAN configuration parameters for database with db_unique_name TEST0221 are:

CONFIGURE RETENTION POLICY TO REDUNDANCY 2;

CONFIGURE BACKUP OPTIMIZATION ON;

CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default

CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default

CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default

CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default

CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default

CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default

CONFIGURE MAXSETSIZE TO UNLIMITED; # default

CONFIGURE ENCRYPTION FOR DATABASE OFF; # default

CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default

CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default

CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default

CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u01/app/oracle/product/11.2.0/dbhome_1/dbs/snapcf_test0221.f'; # default

RMAN> list backup;

specification does not match any backup in the repository

RMAN> sql 'alter tablespace users offline';----------星期一offline

sql statement: alter tablespace users offline

RMAN> backup database; -----------------星期二，全库备份

Starting backup at 06-MAR-14

using channel ORA_DISK_1

channel ORA_DISK_1: starting full datafile backup set

channel ORA_DISK_1: specifying datafile(s) in backup set

input datafile file number=00001 name=/u01/app/oracle/oradata/test0221/system01.dbf

input datafile file number=00002 name=/u01/app/oracle/oradata/test0221/sysaux01.dbf

input datafile file number=00005 name=/u01/app/oracle/oradata/test0221/example01.dbf

input datafile file number=00003 name=/u01/app/oracle/oradata/test0221/undotbs01.dbf

input datafile file number=00004 name=/u01/app/oracle/oradata/test0221/users01.dbf

channel ORA_DISK_1: starting piece 1 at 06-MAR-14

channel ORA_DISK_1: finished piece 1 at 06-MAR-14

piece handle=/u01/app/oracle/fast_recovery_area/TEST0221/backupset/2014_03_06/o1_mf_nnndf_TAG20140306T123613_9khysyg0_.bkp tag=TAG20140306T123613 comment=NONE

channel ORA_DISK_1: backup set complete, elapsed time: 00:01:55

channel ORA_DISK_1: starting full datafile backup set

channel ORA_DISK_1: specifying datafile(s) in backup set

including current control file in backup set

including current SPFILE in backup set

channel ORA_DISK_1: starting piece 1 at 06-MAR-14

channel ORA_DISK_1: finished piece 1 at 06-MAR-14

piece handle=/u01/app/oracle/fast_recovery_area/TEST0221/backupset/2014_03_06/o1_mf_ncsnf_TAG20140306T123613_9khyxm0v_.bkp tag=TAG20140306T123613 comment=NONE

channel ORA_DISK_1: backup set complete, elapsed time: 00:00:02

Finished backup at 06-MAR-14

RMAN> backup database;----------星期三全库备份

Starting backup at 06-MAR-14

using channel ORA_DISK_1

channel ORA_DISK_1: starting full datafile backup set

channel ORA_DISK_1: specifying datafile(s) in backup set

input datafile file number=00001 name=/u01/app/oracle/oradata/test0221/system01.dbf

input datafile file number=00002 name=/u01/app/oracle/oradata/test0221/sysaux01.dbf

input datafile file number=00005 name=/u01/app/oracle/oradata/test0221/example01.dbf

input datafile file number=00003 name=/u01/app/oracle/oradata/test0221/undotbs01.dbf

input datafile file number=00004 name=/u01/app/oracle/oradata/test0221/users01.dbf

channel ORA_DISK_1: starting piece 1 at 06-MAR-14

channel ORA_DISK_1: finished piece 1 at 06-MAR-14

piece handle=/u01/app/oracle/fast_recovery_area/TEST0221/backupset/2014_03_06/o1_mf_nnndf_TAG20140306T123854_9khyyyqz_.bkp tag=TAG20140306T123854 comment=NONE

channel ORA_DISK_1: backup set complete, elapsed time: 00:01:56

channel ORA_DISK_1: starting full datafile backup set

channel ORA_DISK_1: specifying datafile(s) in backup set

including current control file in backup set

including current SPFILE in backup set

channel ORA_DISK_1: starting piece 1 at 06-MAR-14

channel ORA_DISK_1: finished piece 1 at 06-MAR-14

piece handle=/u01/app/oracle/fast_recovery_area/TEST0221/backupset/2014_03_06/o1_mf_ncsnf_TAG20140306T123854_9khz2mf1_.bkp tag=TAG20140306T123854 comment=NONE

channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01

Finished backup at 06-MAR-14