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The essence of RMAN backup is that there are two packages in TARGET DATABASE, DBMS_RCVMAN and DBMS_BACKUP_RESTORE. Backup principle: when backing up, the RMAN client will also initiate a call to the package DBMS_RCVMAN to read and write control files, so that you can know the location of the dbf and other information. Then the RMAN client sends a call request to DBMS_BACKUP_RESTORE, which packages one or more server process to back up the required data blocks to the backup set, and then completes the backup of the database; the recovery principle is similar; the number of server process depends on the setting of this parameter of CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET;. So there are only two packages at the core of RMAN. This is also the core principle of other third-party backup tools. For example, BACKUP DATABASE is a command of RMAN, which translates the interpretation of the local package recovery.bsq on the client into a call to two packages in the target database to complete the backup. Recovery.bsq this file records the interpretation of all RMAN commands and invocation target database package commands.

Configuration information of RMAN RMAN > SHOW ALL

RMAN configuration parameters for database with db_unique_name ORCL are:# configures a redundancy policy. At least one full backup, unit: copy # also has a redundancy policy called recovery window, unit: day # CONFIGURE RETENTION POLICY, follow the default prompt. # the redundancy strategy means that the database can be recovered at any time within 6 days. # that is, you must have the most recent backup data from 6 days ago. # CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 6 DAYS;# [recommended] set 3 redundant backups CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default

# configuration backup optimization # if set to on, for readonly or offline files, RMAN will only back up once # [recommended] off to prevent missing backup data CONFIGURE BACKUP OPTIMIZATION OFF; # default

# back up to disk by default, or back up to tape SBT# [recommended] prepare it to the tape library as much as possible. CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default

# Manual backup has some disadvantages, such as easy to miss backup, not knowing the SCN number and so on. # RMAN finds backup sets based on backup metadata, which is convenient and reliable. # Rman metadata is very important, if lost, the backup set is useless, the metadata is in the control file, so the control file is very important, be sure to back up more # [recommendation] you must open on to control the automatic backup of files. Advantages: in archiving mode, whenever the physical structure of the database changes, such as adding or deleting tablespaces and data # # files, Oracle will automatically # backup control files CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default

# controls the location of file backup, which is in the flashback area by default. # [recommended] add path CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO'% fallow; # default

# configure the parallelism of backup sets # [recommended] 4. For more information, please see the principle of RMAN backup. 1server process maintains RMAN connections and 3server process is responsible for backup. CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default

# configure the number of copy for each backup of the database. There can be multiple identical copies of Oracle for each backup. CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default

# configure the type of device for storing archive logs in the database: CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default

# configure the maximum size of the backup set CONFIGURE MAXSETSIZE TO UNLIMITED; # default

# configure database encryption CONFIGURE ENCRYPTION FOR DATABASE OFF; # default

# configure encryption algorithm AES128CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default

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

# configure archive log deletion policy CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default

# configure the storage path and file name of the snapshot file of the control file, which is generated during the backup and is used to control the read consistency of # documents. CONFIGURE SNAPSHOT CONTROLFILE NAME TO'/ u01qapplash oracleandproduct11.2.0Uniplicatedbhomeowners 1anddbsAccording to snapcfharmorcl.fags; # default

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