You are working on a database that must be functioning 24 hours a day, 7 days a week. The
database is configured in ARCHIVELOG mode. Which two options do you have for performing usermanaged backups? (Choose two.)
A.
You can perform consistent backups only.
B.
You can perform a complete database backup without shutting down the database instance.
C.
You can back up data files only when all data files have the same SCN recorded in the control file.
D.
You can back up only those data files whose headers are frozen by using ALTER TABLESPACE
BEGIN BACKUP or ALTER DATABASE BEGIN BACKUP commands.
Archive mode: can be consistent backup (cold standby) and non-consistent backup (hot standby).
Non-archive mode: consistent backup (cold standby)
Consistent backup (cold backup): do a backup in case the database is shut down, the database is in a consistent state.
(It can be used for archiving and non-archiving), all consistent with the SCN number. Disadvantages: Database needs to close.
Non-consistent backup (hot backup): database backup in open state (for archive mode),
Use alter database / tablespace xxx begin backup to start the backup.
Advantages: The database does not need to shut down for the database 7×24 transaction.
Usually manual backup main backup control files, data files, and parameter files.
First check the control files, data files, and parameter file:
sys @ TEST0910> select name from v $ controlfile;
Manual hot backup:
Open only for the backup archive mode, and before the first Hot Standby Run:
Hot Standby steps:
alter database / tablespace XXX begin backup this sentence will lead to lock physique, No. scn not change.
cp files
alter database / tablespace XXX end backup
Experimental backup users table space, and test and recover deleted files:
1, starting with the table space backup users
sys @ TEST0910> alter tablespace users begin backup;
Tablespace altered.
2, the operating system command to copy the file:
[Oracle @ rtest ~] $ cd / u01 / app / oracle
[Oracle @ rtest oracle] $ mkdir hot_dir
[Oracle @ rtest oracle] $ cp /u01/app/oracle/oradata/test0910/users01.dbf /u01/app/oracle/hot_dir/users01.dbf
3, the end users to back up the table space:
sys @ TEST0910> alter tablespace users end backup;
Tablespace altered.
4, then delete the file users01.dbf
[Oracle @ rtest oracle] $ ls /u01/app/oracle/oradata/test0910/users01.dbf
ls: /u01/app/oracle/oradata/test0910/users01.dbf: No such file or directory
5, off the library, and then start library error:
sys @ TEST0910> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
sys @ TEST0910> startup
ORACLE instance started.
Total System Global Area 2505338880 bytes
Fixed Size 2230952 bytes
Variable Size 587203928 bytes
Database Buffers 1895825408 bytes
Redo Buffers 20078592 bytes
Database mounted.
ORA-01157: can not identify / lock data file 4 – see DBWR trace file
ORA-01110: data file 4: ‘/u01/app/oracle/oradata/test0910/users01.dbf’
6. A copy of the operating system to the correct position (also by rman restore, copy mode used here)
[Oracle @ rtest oracle] $ cp /u01/app/oracle/hot_dir/users01.dbf /u01/app/oracle/oradata/test0910/users01.dbf
[Oracle @ rtest oracle] $ ls /u01/app/oracle/oradata/test0910/users01.dbf
/u01/app/oracle/oradata/test0910/users01.dbf
7, and then open the library, being given, the media need to recover:
sys @ TEST0910> alter database open;
alter database open
*
ERROR at line 1:
ORA-01113: file 4 needs media recovery
ORA-01110: data file 4: ‘/u01/app/oracle/oradata/test0910/users01.dbf’
8, media recovery:
sys @ TEST0910> recover datafile 4;
Media recovery complete.
9, and then open the library, success:
sys @ TEST0910> alter database open;
Database altered.
Recovery Success
The ALTER TABLESPACE … BEGIN BACKUP statement places a tablespace in backup mode.
Consistency is not guaranteed on the hot backup, that is why the header must be frozen.
So, D is correct