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BACKUP & RECOVERY CONCEPTS RMAN




RMAN:
Recovery Manager (RMAN) is an Oracle utility that can back up, restore, and recover database files. The product is a feature of the Oracle database server and does not require separate installation.
Recovery Manager is a client/server application that uses database server sessions to perform backup and recovery.
RMAN must include the following components:

A TARGET DATABASE:
An Oracle database, To which RMAN is connected with the TARGET keyword.  A target database is a database on which RMAN is performing backup and recovery operations. RMAN always maintains metadata about its operations on a database in the control file of the database. The RMAN metadata is known as the RMAN repository.

RMAN CLIENT:
The RMAN executable is automatically installed with the database and is typically located in the same directory as the other database executables. For example, the RMAN client on Linux is located in $ORACLE_HOME/bin.

Some environments use the following optional components:

A fast recovery area:
A disk location in which the database can store and manage files related to backup and recovery. You set the fast recovery area location and size with the DB_RECOVERY_FILE_DEST and DB_RECOVERY_FILE_DEST_SIZE initialization parameters.

A media manager:
An application required for RMAN to interact with sequential media devices such as tape libraries. Media management devices are sometimes called SBT (system backup to tape) devices.

A recovery catalog:
A separate database schema used to record RMAN activity against one or more target databases. A recovery catalog preserves RMAN repository metadata if the control file is lost, making it much easier to restore and recover following the loss of the control file. The database may overwrite older records in the control file, but RMAN maintains records forever in the catalog unless the records are deleted by the user.

Connect to RMAN like below

C:\Users\>rman
Recovery Manager: Release 10.2.0.1.0 - Production on Tue May 26 12:35:45 2015
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
RMAN> connect target sys@XE
target database Password:
connected to target database: XE (DBID=2761439438)
RMAN> exit
Recovery Manager complete.
  
C:\Users\>rman target sys/cherry@XE
Recovery Manager: Release 10.2.0.1.0 - Production on Tue May 26 12:40:37 2015
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
connected to target database: XE (DBID=2761439438)

The following example appends the output from an RMAN session to a text file at /tmp/msglog.log & D:\DATA_XE\RMAN\msglog.log

Windows:
C:\Users\>rman TARGET sys/cherry@XE LOG 'D:\DATA_XE\RMAN\msglog.log' APPEND

Linux:
$rman TARGET / LOG /tmp/msglog.log APPEND

Backing Up a Database in NOARCHIVELOG Mode using RMAN

If a database runs in NOARCHIVELOG mode. For the backup to be consistent, the database must be mounted after a consistent shutdown. No recovery is required after restoring the backup. 

SQL> shut immediate
SQL> startup mount
RMAN> backup database format ‘D: \DATA_XE\RMAN\’
Once backup completed successfully.
SQL> Alter database open.
NOTE: if the database is in noarchivelog mode. We can only take backup in the mount state using RMAN. We cannot take in open state. Please see below example.
SQL> shut immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.

Total System Global Area 805306368 bytes
Fixed Size                  1289996 bytes
Variable Size             218104052 bytes
Database Buffers          583008256 bytes
Redo Buffers                2904064 bytes
Database mounted.
SQL> alter database noarchivelog;
Database altered.

SQL> alter database open;
Database altered.



C:\Users\ >rman
Recovery Manager: Release 10.2.0.1.0 - Production on Tue May 26 14:52:23 2015
Copyright (c) 1982, 2005, Oracle.  All rights reserved.

RMAN> connect target sys@XE
target database Password:
connected to target database: XE (DBID=2761439438)

RMAN> backup database;
Starting backup at 26-MAY-15
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=25 devtype=DISK
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 05/26/2015 14:52:51
ORA-19602: cannot backup or copy active file in NOARCHIVELOG mode

RMAN> show all;

RMAN configuration parameters are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 2;
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO 'D:\DATA_XE\RMAN%F';
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 CHANNEL 1 DEVICE TYPE DISK FORMAT   'D:\DATA_XE\RMAN\XE_%U/%d/%t/%s/%p';
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO 'D:\XE\APP\ORACLE\PRODUCT\10.2.0\SERVER\DATABASE\SNCFXE.ORA'; # default
CONFIGURE CHANNEL 1 DEVICE TYPE DISK FORMAT   'D:\DATA_XE\RMAN\XE_%U';
CONFIGURE CHANNEL 1 DEVICE TYPE DISK FORMAT   'D:\DATA_XE\RMANXE_%U%d%t%s%p';

FORMAT:
The most common substitution variable is %U, which generates a unique name. Others include %d for the DB_NAME, %t for the backup set time stamp, %s for the backup set number, and %p for the backup piece number.

TAG:
Specifies a user-defined string as a label for the backup. If you do not specify a tag , then RMAN assigns a default tag with the date and time. Tags are always stored in the RMAN repository in uppercase.

RMAN> backup database TAG 'XE_DB_BACKUP';
Starting backup at 26-MAY-15
using channel ORA_DISK_1
channel ORA_DISK_1: starting full data file backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00003 name=D:\XE\ORADATA\XE\SYSAUX.DBF
input datafile fno=00001 name=D:\XE\ORADATA\XE\SYSTEM.DBF
input datafile fno=00005 name=D:\DATA_XE\DF\TEST.01.DBF
input datafile fno=00004 name=D:\XE\ORADATA\XE\USERS.DBF
input datafile fno=00002 name=D:\XE\ORADATA\XE\UNDO.DBF
channel ORA_DISK_1: starting piece 1 at 26-MAY-15
channel ORA_DISK_1: finished piece 1 at 26-MAY-15
piece handle=D:\DATA_XE\RMANXE_0RQ7TOGL_1_1XE880730645271 tag=XE_DB_BACKUP comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:45
Finished backup at 26-MAY-15

Starting Control File and SPFILE Autobackup at 26-MAY-15
piece handle=D:\DATA_XE\RMANC-2761439438-20150526-06 comment=NONE
Finished Control File and SPFILE Autobackup at 26-MAY-15

INCREMENTAL BACKUP:
An incremental backup is a type of backup that only copies files that have changed since the last backup but an incremental backup at level 0 is identical in content to a full backup. A level 1 incremental backup contains only blocks changed after a previous incremental backup.

If we specify BACKUP INCREMENTAL, then RMAN creates an incremental backup of a database. Incremental backups capture block-level changes to a database made after a previous incremental backup. Incremental backups are generally smaller and faster to make than full database backups. Recovery with incremental backups is faster than using redo logs alone.

NOTE: If no level 0 backup exists in either the current or parent database incarnation when you run a level 1 backup, then RMAN makes a level 0 backup automatically.

NOTE: You cannot make incremental backups when a NOARCHIVELOG database is open, although you can make incremental backups when the database is mounted after a consistent shutdown.

RMAN> backup incremental level 0 database; - Consider as a full database backup.

Please below marked in RED

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
21      Incr 0  670.46M    DISK        00:00:57     26-MAY-15
        BP Key: 21   Status: AVAILABLE  Compressed: NO  Tag: TAG20150526T202511
        Piece Name: D:\DATA_XE\RMANXE_0TQ7UA58_1_1XE880748712291
  List of Datafiles in backup set 21
  File LV Type Ckp SCN    Ckp Time  Name
  ---- -- ---- ---------- --------- ----
  1    0  Incr 536121     26-MAY-15 D:\XE\ORADATA\XE\SYSTEM.DBF

RMAN> backup incremental level 1 database; - Here it will back up only the modified blocks 

after level 0 backup.

 Please below marked in RED:

 BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
23      Incr 1  328.00K    DISK        00:00:20     26-MAY-15
        BP Key: 23   Status: AVAILABLE  Compressed: NO  Tag: TAG20150526T204006
        Piece Name: D:\DATA_XE\RMANXE_0VQ7UB17_1_1XE880749607311
  List of Datafiles in backup set 23
  File LV Type Ckp SCN    Ckp Time  Name
  ---- -- ---- ---------- --------- ----

  1    1  Incr 536516     26-MAY-15 D:\XE\ORADATA\XE\SYSTEM.DBF

RMAN>BACKUP INCREMENTAL LEVEL 1 CUMULATIVE DATABASE; - A level 1 backup can be a cumulative incremental backup, which includes all blocks changed since the most recent level 0 backup

NOTE: When restoring incremental backups, RMAN uses the level 0 backup as the starting point, then updates changed blocks based on level 1 backups where possible to avoid reapplying changes from redo one at a time. Recovering with incremental backups requires no additional effort on your part. If incremental backups are available, then RMAN uses them during recovery.

Validating Database Files and Backups:
The VALIDATE command to confirm that all database files exist, are in their correct location, and are free of physical corruption. The CHECK LOGICAL option also checks for logical block corruption.

Following commands to validate all database files and archived redo log files for physical and logical corruption:

RMAN>BACKUP VALIDATE CHECK LOGICAL DATABASE ARCHIVELOG ALL;

Validate backup sets, as shown in the following example:

RMAN> VALIDATE BACKUPSET 21;
using channel ORA_DISK_1
channel ORA_DISK_1: starting validation of datafile backupset
channel ORA_DISK_1: reading from backup piece D:\DATA_XE\RMANXE_0TQ7UA58_1_1XE880748712291
channel ORA_DISK_1: restored backup piece 1
piece handle=D:\DATA_XE\RMANXE_0TQ7UA58_1_1XE880748712291 tag=TAG20150526T202511
channel ORA_DISK_1: validation complete, elapsed time: 00:00:09

Reporting on RMAN Operations:

Run the LIST BACKUP and LIST COPY commands to display information about backups and data file copies listed in the repository.

RMAN> LIST BACKUP OF DATABASE BY BACKUP; - Organizes the output by backup set. This is the default mode of presentation.

RMAN> LIST BACKUP BY FILE; - List the backup according to which file was backed up.


RMAN> LIST BACKUP SUMMARY; - Displays summary output.

Additional LIST Options:

Lists backups that are recorded in the RMAN repository but that were not present at the expected location on disk or tape during the last CROSSCHECK command. An expired backup may have been deleted by an operating system utility.
RMAN> LIST EXPIRED COPY;

Lists data file backups or copies that have status AVAILABLE in the RMAN repository and that can be restored and recovered.
RMAN> LIST BACKUP RECOVERABLE;


Can display specific objects, as in the following examples:

RMAN> LIST BACKUP OF DATABASE;
RMAN> LIST COPY OF DATAFILE 1, 2;
RMAN> LIST BACKUP OF ARCHIVELOG FROM SEQUENCE 10;

RMAN> LIST BACKUPSET OF DATAFILE 1;


RMAN> REPORT SCHEMA;

Report of database schema

List of Permanent Datafiles
===========================
File Size(MB) Tablespace           RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1    340      SYSTEM               ***     D:\XE\ORADATA\XE\SYSTEM.DBF
2    90       UNDO                 ***     D:\XE\ORADATA\XE\UNDO.DBF
3    450      SYSAUX               ***     D:\XE\ORADATA\XE\SYSAUX.DBF
4    100      USERS                ***     D:\XE\ORADATA\XE\USERS.DBF
5    200      TEST                 ***     D:\DATA_XE\DF\TEST.01.DBF

List of Temporary Files
=======================
File Size(MB) Tablespace           Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1    20       TEMP                 32767       D:\XE\ORADATA\XE\TEMP.DBF

RMAN> REPORT OBSOLETE;

RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 2
Report of obsolete backups and copies
Type                 Key    Completion Time    Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set           22     26-MAY-15
  Backup Piece       22     26-MAY-15          D:\DATA_XE\RMANC-2761439438-20150526-07

RMAN> REPORT UNRECOVERABLE;

Report of files that need backup due to unrecoverable operations
File Type of Backup Required Name
---- ----------------------- -----------------------------------

RMAN>   REPORT NEED BACKUP DATABASE;

RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 2
Report of files with less than 2 redundant backups
File #bkps Name
---- ----- -----------------------------------------------------
1    1     D:\XE\ORADATA\XE\SYSTEM.DBF
2    1     D:\XE\ORADATA\XE\UNDO.DBF
3    1     D:\XE\ORADATA\XE\SYSAUX.DBF
4    1     D:\XE\ORADATA\XE\USERS.DBF
5    1     D:\DATA_XE\DF\TEST.01.DBF


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