Customizable Configuration Parameters
TheCONFIGURE
command can be used to set certain parameters once for all subsequent jobs. This data is stored in a controlfile which can be resynchronized to the recovery catalog.A Rentention Policy defines which backup are no longer needed. This can be configured in one of two ways:
[@more@]CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS; CONFIGURE RETENTION POLICY TO REDUNDANCY 5; CONFIGURE RETENTION POLICY TO NONE;
Recovery Manager (RMAN) Enhancements In Oracle9i
Customizable Configuration Parameters
TheCONFIGURE
command can be used to set certain parameters once for all subsequent jobs. This data is stored in a controlfile which can be resynchronized to the recovery catalog.A Rentention Policy defines which backup are no longer needed. This can be configured in one of two ways:
The recovery window is used to make sure that there are always sufficent backups to recover the database to ant point in time with the last 'X' days. Any backups that fall outside this time period can be deleted. The redundancy option simply states that any backups in excess of the latest 'X' are no longer needed. The default redundancy is 1 copy. The safest option is to use the redundancy window as several backups on a single day could cause the redundancy option to mark valuable files as redundant. FInally, the redundancy policy can be cleared.CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS; CONFIGURE RETENTION POLICY TO REDUNDANCY 5; CONFIGURE RETENTION POLICY TO NONE;
If multiple copies of each backup are required this can be configured using:
TheCONFIGURE [DATAFILE | ARCHIVELOG] BACKUP COPIES FOR DEVICE TYPE TO
SET BACKUP COPIES
command can be used to overide the default settings for individual jobs where required.All I/O operations require the device type to be set to disk or tape. A default value for this setting can defined using:
The default degree of parallelism for the device type can also also be configured such that when a command is issued the specific number of channels are allocated to the process:CONFIGURE DEFAULT DEVICE TYPE TO [DISK | SBT];
Default channels can be defined and removed using:CONFIGURE DEVICE TYPE DISK PARALLELISM 4;
The configure command can be used to exclude tablespaces from backups. This is especially useful for read-only tablespaces:CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT 'C:OracleBackupTSH1%d_DB_%u_%s_%p'; CONFIGURE CHANNEL DISK CLEAR;
The configure command can be used to force a controlfile autobackup after all backup and run commands to allow controlfile recovery if the controlfile is lost and the recovery catalog was not used or is unavailable:CONFIGURE EXCLUDE FOR TABLESPACE [CLEAR];
The controlfile is stored using the formatCONFIGURE CONTROLFILE AUTOBACKUP [ON | OFF]; RESTORE CONTROLFILE FROM AUTOBACKUP;
c-IIIIIIIIII-YYYYMMDD-QQ
which represents the database identifier, the datestamp of the backup and a hexidecimal sequence.Finally, two commands have been renamed to bring them in line with the new configure command:
-- Formerly SET SNAPSHOT CONTROLFILE CONFIGURE SNAPSHOT CONTROLFILE; -- Formerly SET AUXNAME CONFIGURE AUXNAME;
Backup And Restore Enhancements
The KEEP option of the backup command can be used to retain backups for longer than the retention policy indicates:A multi-values format option is now available when creating mirrored backups. RMAN performs the first copy with the first format, the second copy with the second format etc. If more copies are defined than formats, RMAN returns to the start of the format list and uses the that format. If less copies are defined than formats, the extra formats are ignored:BACKUP DATABASE KEEP UNTIL TIME "TO_DATE('01-JAN-2003','DD-MON-YYYY')" NOLOGS; BACKUP TABLESPACE tbs1 KEEP FOREVER NOLOGS; BACKUP DATABASE KEEP; CHANGE BACKUPSET 225 NOKEEP;
Backup file optimization can be used to prevent repeat backups of read-only tablespaces and archive logs:RUN { SET BACKUP COPIES 3; BACKUP DATABASE FORMAT '/dir1/%U','/dir2/%U','/dir3/%U'; }
- Read-only and offline-clean data files are only backed up once per recovery window.
- The command
BACKUP ARCHIVELOG ALL
only backs up logs that are not already on tape. - The command
BACKUP BACKUPSET ALL
copies to tape all backup sets that do not already exist on tape.
If your current media manager has it's own expiration policy this may interfere with backup optimization. Periodic synchronization between RMAN and the media manager can be performed usingCONFIGURE BACKUP OPTIMIZATION [ON | OFF | CLEAR];
CROSSCHECK
.Restartable backups allow failed backups to be restarted where they left off using the
SINCE TIME
option:Archive logs can now be backed up along with datafiles using theBACKUP DATABASE NOT BACKED UP SINCE TIME '15-JAN-01 01:00:00'; BACKUP DATABASE NOT BACKED UP SINCE TIME 'SYSDATE - 1';
PLUS ARCHIVELOG
option. This is the default action when backing up to tape:This command results in:BACKUP DATAFILE 2 PLUS ARCHIVELOG;
ALTER SYSTEM ARCHIVE LOG CURRENT
BACKUP ARCHIVELOG ALL
BACKUP
of specified files.ALTER SYSTEM ARCHIVE LOG CURRENT
BACKUP
of any archived logs generated during the backup.
It is now possible for RMAN to copy or move backupsets from disk to tape using the
BACKUPSET
option:The range of backupsets can be limited using theBACKUP DEVICE TYPE SBT BACKUPSET ALL;
CREATED BEFORE
option, with the DELETE INPUT
option turning the copy into a move operation:Restore operations are now optimized such that if the current datafile header is consistent with the backup datafile it will be skipped. This prevents unnecessary restores and allows for restartable restore operations. Only file headers are checked when making this decision. If you suspect a file contains block corruption you must use theBACKUP DEVICE TYPE SBT BACKUPSET CREATED BEFORE 'SYSDATE - 7' DELETE INPUT;
FORCE
option for an unconditional restore of the file.Oracle Enterprise Manager has been updated to include all the new RMAN functionality.
Reliability Enhancements
Archive log failover allows RMAN can take advantage of multiple archive logs destinations such that, if a corrupt log is detected it can read the log from the alternate destination.The
DELETE ALL INPUT
option can be used along with the BACKUP ARCHIVELOG
command to delete archive logs from multiplexed destinations once they've been sucessfully backed up.RMAN performs automatic log switches at the end of any backup or copy operations. The resulting log is archived to increase the chances of sucessful recovery.
If multiple copies of backup pieces are created at different locations RMAN can use backup piece failover during restore operations. If a backup piece is invalid or corrupt an alternate copy is used. An error will only be issued if a valid copy cannot be found.
Block Media Recovery (BMR) allows specified blocks to be recovered without affecting the entire datafile. It is only intended for use where a known and limited number of blocks is affected. This results in a reduced mean time to recovery (MTTR) and higher availability as only the affected blocks are offline during the operation. BMR can only be performed via RMAN using the
BLOCKRECOVER
command.Corrupt blocks can be identified using:
- Error messages
- The alert log
- Trace files
ANALYZE [TABLE | INDEX]
commands- The dbverify utility
- The
V$BACKUP_CORRUPTION
&V$COPY_CORRUPTION
views list corrupt blocks in the backups, not the database itself. - The new view
V$DATABASE_BLOCK_CORRUPTION
lists corrupt blocks in the database detected during the backup operation. Recovered blocks will still be listed until the next backup is performed.
CORRUPTION LIST
option can be used to recover all blocks listed in the V$DATABASE_BLOCK_CORRUPTION
view. This list can be limited using the UNTIL
option:BLOCKRECOVER DATAFILE 3 BLOCK 121; BLOCKRECOVER CORRUPTION LIST RESTORE UNTIL TIME 'SYSDATE - 7';
General Enhancements
TheREPORT OBSOLETE
command now displays obsolete archive logs as well as datafiles. In addition the DELETE OBSOLETE
command can be used to delete those files listed by the REPORT OBSOLETE
command.The
REPORT NEED BACKUP
command now reports files needing backup according to the retention policy:If a recovery catalog is not specified all commands assume the control file should be used to store backup and recovery information. With this in mind several RMAN commands such asREPORT NEED BACKUP DAYS 3 TABLESPACE SYSTEM; REPORT NEED BACKUP INCREMENTAL 3 DATABASE;
LIST
, CROSSCHECK
, DELETE
and CHANGE
can now function using a recovery catalog or the controlfile. The
LIST
command can now output data in two orientations:TheLIST BACKUP .... BY [BACKUP | FILE] [SUMMARY | VERBOSE];
BY BACKUP
orientation shows backupsets and their contents alonmg with backup copies of any file. This is the default providing no OF
option is specified. The SUMMARY
option gives a one-line summary for each file or backupset. The BY FILE
orientation shows the file name, backupset it's from and copies of the file.The
SHOW
command is used to display the values of current CONFIGURE
commands:In Real Application Clusters (RAC) different objects can exist only on a single node, but may exist on disk or tape. Using multiple channels, the newSHOW RETENTION POLICY, DEFAULT DEVICE TYPE; SHOW ALL;
CROSSCHECK
autolocate functionality simplifies the process of finding backup pieces on multiple nodes.The RMAN display is neater since RMAN-nnnnn messages are only printed when errors occur. Oracle Manages Files (OMF) are now supported by RMAN. If files with differing block sizes are backed up in the same command RMAN will separate them into different backup sets. By default RMAN uses the
NOCATALOG
option menaing the controlfile is used for backup and recovery information.来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/330796/viewspace-884717/,如需转载,请注明出处,否则将追究法律责任。
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