复制数据库两种方式:
- 采用命令行方式
- 采用OEM方式
Ensuring That Backups and Archived Redo Log Files Are Available
- Backups of all target database files must be accessible on the duplicate host.
- Backups can be a combination of full and incremental backups.
- Archived redo log files needed to recover the duplicate database must be accessible on the duplicate host.
- Archived redo log files can be:
- Backups on a media manager
- Image copies
- Actual archived redo log files
Allocating Auxiliary Channels
- Auxiliary channels specify a connection between RMAN and an auxiliary database instance.
- If automatic channels are not configured,allocate auxiliary channels:
- Start RMAN with a connection to the target database instance,the auxiliary instance,and recovery catalog if applicable.
- Allocate at least one auxiliary channel within the RUN block.
$ rman target sys/oracle_4U@trgt auxiliary sys/oracle_4U@auxdb RMAN> RUN { ALLOCATE AUXILIARY CHANNEL aux1 DEVICE TYPE DISK; ALLOCATE AUXILIARY CHANNEL aux2 DEVICE TYPE DISK; ... DUPLICATE TARGET DATABASE to auxdb;... }
Understanding the RMAN Duplication Operation
When you execute the DUPLICATE command,RMAN performs the following operations:
- 1A.Create a control files server parameter file for the auxiliary instance(for active and for backup-based duplication with target connection)
- 1B.Restores from backup(for standby database and for backup-based duplication without target connection)
- 2.Mounts the backup control file
- 3.For backup-based duplication:Selects the backups for restoring the data files to the auxiliary instance
- 4.Restores the target data files to the duplicate database
- 5.Performs incomplete recovery using all available increamental backups and archived redo log files.
- 6.Shuts down and restarts the auxiliary instance in NOMOUNT mode
- 7.Creates a new control file,which then creates and stores the new DBID in the data files
- 8.Opens the duplicate database with the RESETLOGS option
- 9.Creates the online redo log files for the duplicate database
Note:The database duplication process attempts to resume from the point-of-failure upon reexecution.(duplicate database and recovery database are simlar with this)
Specifying Options for the DUPLICATE Command
You can specify the following options with the DUPLICATE command:
| Option | Purpose |
| SKIP READONLY | Excludes read-only tablespaces |
| SKIP TABLESPACE | Excludes named tablespaces |
| TABLESPACE | Includes named tablespaces |
| NOFILENAMECHECK | Prevents checking of file names |
| OPEN RESTRICTED | Enables RESTRICTED SESSION automatically |
| REDO |
Signals RMAN that the application of redo logs should be suppressed during recovery Must be used with targetless DUPLICATE when target database is in NOARCHIVELOG mode at backup time Can also be used to explicitly state that no archived redo log files should be applied |
| UNDO TABLESPACE | Must be specified when target database is not open and there is no recovery catalog connection so that RMAN does not check the tablespace for SYS-owned objects |
Using OEM to clone a database
