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DBA - Recovery Manager (RMAN)

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• DBA - Recovery Manager (RMAN)
  • Commands
  • Oracle Recovery Manager (RMAN)
    • Connecting to RMAN and a Target Database
    • Using SQL in RMAN
  • Types of RMAN Commands
    • Job commands
  • Configuring Persistent Settings for RMAN
    • View all RMAN persistent settings
    • Managing Persistent Settings
  • Lab
    • Backup Database
    • Setting the Date and Time Format for RMAN
    • View RMAN Configuration
    • Backup Tablespace
    • Direct the Output to a File

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Commands

RMAN Command	Description
host 'clear screen';	Clear screen
host 'clear';	Clear screen
show all;	List all persistent settings
show <setting>;	Show a persistent setting
configure <setting> <value>;	Configure a persistent setting
configure <setting> clear;	Set a persistent setting back to default
RESYNC CATALOG	Execute catalog resynchronization
BACKUP DATABASE	Backup the entire database
ALLOCATE CHANNEL	Allocate a channel for executing a job command

• Retention Policy

RMAN Command	Description
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF <days> DAYS;	Configure the recovery window retention policy
CONFIGURE RETENTION POLICY TO REDUNDANCY <copies>;	Configure the redundancy retention policy
CONFIGURE RETENTION POLICY TO NONE;	Disable the retention policy

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Oracle Recovery Manager (RMAN)

• Oracle Recovery Manager (RMAN)

  • is the core Oracle Database software component that manages database backup, restore, and recovery processes.
  • maintains configurable backup and recovery policies and keeps historical records of all database backup and recovery activities.
  • ensures
    • that all files required to successfully restore and recover a database are included in complete database backups.
    • all data blocks are verified to ensure that corrupt blocks are not propagated into the backup files.

• RMAN uses

  • the fast recovery area for backups.
  • Optionally, Oracle Secure Backup, so backups can be made to the tape drive and to the cloud. Backups can be performed to other designated locations, such as directly to disk.

• Intrinsic knowledge of database file formats and recovery procedures
  • Tablespace and data file recovery
  • Block validation
  • Online block-level recovery
  • Online, multistreamed backup
  • Unused block compression
  • Native encryption
• Integrated disk, tape, and cloud backup leveraging the fast recovery area and Oracle Secure Backup

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Connecting to RMAN and a Target Database

• In your Linux course environment, you have more than one local database.

  • . oraenv to set your environment variables.

• Invoke RMAN at the operating system command line and specify the appropriate options. Commonly used options are:

  • target: The connect-string for the target database
  • catalog: The connect-string for a recovery catalog
  • nocatalog: Specifies there is no recovery catalog.
    • the default.
  • cmdfile: The name of an input command file
  • log: The name of the output message log file

• The RMAN invocation rman target / connects to the local database as the target.

# call oraenv script to set environment vairable
. oraenv

# rman connect to the local db with the sYSBACKUP privilege.
rman target "'/ as sysbackup'"

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Using SQL in RMAN

• You can execute SQL commands and PL/SQL procedures from the RMAN command line.

  • The SQL keyword is optional, but you should use it to eliminate ambiguity, especially for a few commands that exist in both RMAN and SQL and have different uses.

  • The RMAN DESCRIBE command provides the functionality of the SQL\*Plus DESCRIBE command. You can use the abbreviated version DESC or the spelled-out DESCRIBE to list the column definitions of a table or view.
  • To access a table or view in another schema, you must have SELECT privileges on the object or connect in the SYSDBA mode.(sysdba 有全权限, 默认 sysbackup 没有 select any 权限)

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Types of RMAN Commands

• two basic types of RMAN commands: stand-alone and job commands.

  • Stand-alone commands
    • executed at the RMAN prompt and are generally self-contained.

  • Job commands - usually grouped and executed sequentially inside a command block.

    • If any command within the block fails, RMAN ceases processing; no further commands within the block are executed. The effects of any already executed commands still remain, though; they are not undone in any way.
    • e.g., ALLOCATE CHANNEL.
      • The channel is allocated only for the execution of the job, so it cannot be issued as a stand-alone command.不能单独执行
  • There are some commands that can be issued either at the prompt or within a RUN command block, such as BACKUP DATABASE.
    • If you issue stand-alone commands, RMAN allocates any needed channels by using the automatic channel allocation feature.

• You can execute stand-alone and job commands in interactive mode or batch mode. 两模式都可以

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• RMAN commands are of the following types:

  • Stand-alone command:

    • Is executed individually at the RMAN prompt
    • Cannot appear as subcommands within RUN

  • Job command:

    • Must be within the braces of a RUN command
    • Is executed as a group

• Some commands can be executed as both types.

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Job commands

• Unlike stand-alone commands, job commands must appear within the braces of a RUN command.

  • Any configurations made within the run block apply within the scope of the block and override any previously made settings.

• e.g.:

• RMAN executes the job commands inside a RUN command block sequentially.

  • If any command within the block fails, RMAN ceases processing. No further commands within the block are executed.
  • When the last command within a RUN block completes, the Oracle database releases any server-side resources such as input/output (1/0) buffers or I/O slave processes allocated within the block.

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Configuring Persistent Settings for RMAN

• Persistent configuration settings

  • control many aspects of RMAN’s behavior
  • always stored in the control file and in the recovery catalog database (if it exists).
  • have default values

• CONFIGURE command

  • used to configure persistent settings:

    • Configure automatic channels
    • Specify the backup retention policy
    • Specify the number of backup copies to be created
    • Set the default backup type to BACKUPSET or COPY
    • Limit the size of backup pieces
    • Exempt a tablespace from backup
    • Enable and disable backup optimization
    • Configure automatic backups of control files
    • Define the archive log deletion policy
    • Specify the parallelism for a device

    • Set the encryption and compression parameters to be used for backups

    • These settings are in effect for any RMAN session until the configuration is cleared or changed.一旦设置则长期有效直到被清除或修改

• SET command

  • used to change the configuration settings in an RMAN job (or session) just for the duration of the job (or session) with the.

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View all RMAN persistent settings

• to view all configuration settings

-- RMAN command to view all configuration settings
SHOW ALL;

-- sql command to display configuration settings that have been explicitly set.
SQL 'select * from V$RMAN_CONFIGURATION';
-- if no explicit settings, nothing returns.

• In the multitenant DB, each entry in V$RMAN_CONFIGURATION has a con_id value:
  • 0 means the configuration applies to the entire CDB,
  • 1 means it applies to the root container only, and any other value means that it applies to the container ID of the PDB only.

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Managing Persistent Settings

• Parallelism

  • the number of streams of data that can be used to read from and write to the device.
  • define the number of channels to be allocated when the device is used by RMAN.
    • e.g., if a media manager has two tape drives available, parallelism 2 would allow both tape drives to be used simultaneously for BACKUP commands using that media manager.
  • Parallelism for the disk device type is also useful, when you want to spread out a backup over multiple disks.
    • e.g.,

-- where <n> is the parallelism value.
CONFIGURE DEVICE TYPE <device> PARALLELISM <n>

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• SHOW command

  • view the RMAN configuration settings.

SHOW CONTROLFILE AUTOBACKUP FORMAT;
SHOW EXCLUDE;
SHOW ALL;

• SHOW AL

  • only node-specific configurations and database configurations are displayed.

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• CONFIGURE command + CLEAR option:
  • to reset any persistent setting to its default value

CONFIGURE BACKUP OPTIMIZATION CLEAR;
CONFIGURE MAXSETSIZE CLEAR;
CONFIGURE DEFAULT DEVICE TYPE CLEAR;

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Lab

Backup Database

• The DB_RECOVERY_FILE_DEST parameter specifies the default location for the fast recovery area. - View the parameter value by logging in to SQL*Plus and using the SHOW PARAMETER command.

-- in sqlplus
show parameter db_recovery_file_dest

-- in rman
BACKUP DATABASE;

Include all datafiles of CDB and all PDBs, along with control file and parameter file will be backed up. By default, using backup set

• Confirm in the FRA

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Setting the Date and Time Format for RMAN

• Use the editor of your choice (vi, gedit) and add the following two lines to the end of the
  • ~oracle/.bashrc file:
  • export NLS_LANG=american_america.al32utf8
  • export NLS_DATE_FORMAT="yyyy-mm-dd:hh24:mi:ss"

# edite bash script
vi ~oracle/.bashrc

# apply bash script to export env var
. ~oracle/.bashrc

• Login RMAN to list backups

list backup;

• By default, date format does not include the time of day information.

• After update the shell script

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View RMAN Configuration

-- Displays whether RMAN is configured to automatically back up the control file and server parameter file whenever a backup or copy operation is performed.
show controlfile autobackup;

-- Displays the retention policy settings for backups, which specify how long to keep backups and how they should be managed.
show retention policy;

-- Provides a summary report of the database schema, including information about the datafiles, tablespaces, and their sizes.
REPORT SCHEMA;

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Backup Tablespace

• Back up the USERS tablespace in both the CDB and PDB1.

BACKUP TABLESPACE users, PDB1:USERS;

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Direct the Output to a File

• Using SPOOL LOG TO <file>

• Create a file for logging

-- do not use ~ for home,
-- rman will create the file
SPOOL LOG TO /tmp/test.log
-- will not display
List Backup
-- stop directing output to the file.
SPOOL LOG OFF

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