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Module 16b recovery manager
- 2. 4/29/2016 Module 16b Recovery Manager http://www.siue.edu/~dbock/cmis565/module16brecovery_manager.htm 2/15 Fast Recovery Area – This is a location on disk to store all RMAN backups. For the USER350 database, this is located at: /u01/app/oracle/fast_recovery_area RMAN Features Major features of RMAN not available with traditional backup methods (operating system) or that improve significantly on traditional backup methods include: Skip unused blocks – Blocks that have never been written to in a table are not backed up by RMAN when the backup is to a RMAN backupset. Backup compression – RMAN provides a binary compression mode that optimizes compression for the typical kind of data found in Oracle data blocks. This slightly increases the CPU time required for backup and recovery. Open database backups – Tablespace backups with RMAN can be done without using BEGIN/END BACKUP clause – still must be in ARCHIVELOG mode. True incremental backups – RMAN does not write unchanged blocks since the last backup. Blocklevel recovery – RMAN supports blocklevel recovery to enable restoring or repairing a small number of blocks identified as being corrupt during the backup operation – keeps the rest of the tablespace online. Multiple I/O Channels – RMAN supports multithreaded operations for backup and recovery. Platform independence – Backups written with RMAN commands are syntactically identical regardless of the operating system or hardware platform. Tape manager support – all major enterprise backup systems from 3rd parties support RMAN. Cataloging – a record of all RMAN backups are recorded in the target database control files – or optionally to a recovery catalog stored in a different database. Scripting capabilities – RMAN scripts can be saved in a recovery catalog for retrieval during backup sessions. Backup Types Consistent and Inconsistent Backups – a physical backup is consistent when all datafiles have the same SCN – this only results when all changes in redo log files have committed to datafiles. An inconsistent backup results when the database is open and system users are using the database. Full backup – includes all blocks of every datafile – essentially a bitforbit copy. Incremental backup – RMAN supports incremental backups as level 0 or level 1. o Level 0 – a full backup of all blocks. o Level 1 – backup of only changed blocks. Image Copies – these are full backups done with operating system commands such as the LINUX/UNIX cp command, or the RMAN backup as copy commands. Backupsets and Backup Pieces – in contrast to Image Copies, backupsets can be created and restored only with RMAN. o A backupset is an RMAN backup of part or all of a database consisting of one or more backup pieces. o Each backup piece belongs to only one backupset and can contain backups of one or more datafiles in the database. Compressed Backups – Compressed backups are only usable by RMAN and require no special processing in a recovery operation – compression is automatic with RMAN. Overview of RMAN Commands/Options Frequently Used Commands This table gives a list of common RMAN commands – see the Oracle Database Recovery Manager Reference for a complete listing. Command Description @ Runs an RMAN script at the pathname specified after @. Default is current path. BACKUP Performs an RMAN backup with or without archived redo log files. Backs up datafiles, datafile copies, or performs incremental level 0 or level 1 backup. Also validates blocks to backed up with the VALIDATE clause. CHANGE Changes status of backup in RMAN repository – used to exclude a backup from a restore/recovery operation. Also used to notify RMAN that a backup file was removed by an operating system command outside of RMAN. CONFIGURE Configures RMAN persistent parameters. These parameters are available for subsequent sessions unless explicitly cleared/modified. CREATE CATALOG Creates a repository catalog with RMAN metadata for one (or more) target databases. CROSSCHECK Checks records of RMAN repository against actual disk or tape files. DELETE Deletes backup files or copies – removes the record of the backup file from the repository. FLASHBACK Performs a Flashback Database operation such as restoration to a point in time by SCN or log sequence. LIST Displays information about backupsets and image copies. RECOVER Performs complete or incomplete recovery on a datafile, tablespace, or entire database. Can apply
- 3. 4/29/2016 Module 16b Recovery Manager http://www.siue.edu/~dbock/cmis565/module16brecovery_manager.htm 3/15 incremental backups to roll forward. REGISTER DATABASE Registers a target database in the RMAN repository. REPORT Provides a detailed analysis of the RMAN repository. RESTORE Restores files from image copies or backupsets to disk – usually after a media failure. Can also be used to validate a restore operation without actually performing the restore by specifying the PREVIEW option. RUN Runs sequence of RMAN statements as a group between { and } – allows overriding RMAN parameters for the group of statements executed. SET Sets RMAN configuration settings for the duration of a RMAN session – not the same as CONFIGURE. SHOW Shows all or individual RMAN configured settings. SHUTDOWN Shuts down the target database with RMAN – same as SHUTDOWN within SQLPlus. STARTUP Starts up the target database with RMAN – same as STARTUP within SQLPlus. SQL Runs SQL commands – example: sql 'ALTER TABLESPACE data01 OFFLINE IMMEDIATE'; before a restore/recover operation. Starting RMAN and Connecting to a Database Use the command rman to connect to the client. dbockstd/@sobora2.isg.siue.edu=>rman Recovery Manager: Release 11.2.0.3.0 Production on Wed Jul 10 12:30:05 2013 Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved. RMAN> Use the CONNECT TARGET command to connect to a target database. RMAN connections to a database are specified and authenticated the same way SQL*Plus is. RMAN connections require SYSDBA privilege. This connects to the target (current ORACLE_SID value) by using operating system authentication this doesn't require a separate password file that would otherwise be required. RMAN> connect target / connected to target database: USER350 (DBID=3391980809) RMAN> How to Persist an RMAN Setting The SHOW ALL command displays default RMAN settings. Notice the target database control file is being used instead of a recovery catalog. Parameters set to default display a # default at the end of the configuration setting. Execute a CONFIGURE command to change any setting. RMAN> show all; using target database control file instead of recovery catalog RMAN configuration parameters for database with db_unique_name DBORCL are: CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default CONFIGURE BACKUP OPTIMIZATION OFF; # default CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default CONFIGURE MAXSETSIZE TO UNLIMITED; # default CONFIGURE ENCRYPTION FOR DATABASE OFF; # default CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default CONFIGURE SNAPSHOT CONTROLFILE NAME TO