RMAN KEY FEATURES
RMAN, Recovery Manager, is a tool to backup, restore
and recover Oracle databases
Can store frequently executed commands as scripts,
independent of OS
Empty blocks are not copied
Provides incremental backup feature to copy only
changed blocks
Can deduct block corruption while taking backup
Parallelize operation to reduce backup time
Can reduce reads per file, thus minimizing impact to
database performance
CONFIGURING TARGET DATABASE
CONNECTING TO THE TARGET DATABASE SSh –X oracle10g @ 10.1.15.91 CREATING LISTENER
Go to netmgr and add a listener CREATING CONNECTION DESCRIPTOR
Add a connection descriptor in netmgr(con_tar) STARTING LISTENER
Start listener using lsnrctl
CONFIGURING CATALOG DATABASE
CREATE LISTENER
o Go to netmgr and add a listener CREATING CONNECTION DESCRIPTOR
o Add a connection descriptor in netmgr(con_cat) STARTING LISTENER
CREATING CATALOG USER
BEFORE CREATING THE CATALOG USER WE WANT TO CREATE A CATALOG TABLESPACE TO HOLD THE CATALOG
Create tablespace cat_tbs
Datafile ‘/home/oracle/product/10.2.0/oradata/cat_tbs.dbf’ size 100m Create user cat identified by cat
Default tablespace cat_tbs Temporary tablespace temp Quota unlimited on cat_tbs Grant connect,resource to cat
Grant recovery_catalog_owner to cat
STEPS TO BE FOLLOWED BEFORE CONNECTING
Database should be in archive log mode
Listeners should be started in both the target and catalog database
Recovery catalog database should be always up and running Target database should be in the mount phase (to read control
files)
CONNECTING THROUGH RMAN
$ RMAN
RMAN > Connect target sys/sys@con_tar RMAN > Connect catalog cat/cat@con_cat RMAN > Create catalog tablespace cat_tbs RMAN > Register database
CONFIGURING RMAN FOR BACKUP
RMAN> show all;
RMAN configuration parameters are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 2; CONFIGURE BACKUP OPTIMIZATION OFF; # default CONFIGURE DEFAULT DEVICE TYPE TO DISK;
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/%F;# default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1; # 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 DEVICE TYPE DISK FORMAT
'/home/oracle/bkp/rman/backup %d_S_%s_P_%p_T_%t'; CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u01/app/oracle/product/9.2.0/dbs/snapcf_ORA920.f'; # default
RMAN Backup Types
Full
backup of a data file that includes every allocated block in the file being backed up
Incremental
level 0 –Backup of every block except blocks compressed out
Level 1- includes blocks that have been changed since the parent backup was taken.
Open
A backup of online, read/write datafiles when the database is open.
Closed
A backup of any part of the target database when it is mounted but not open. Closed backups can be
consistent or inconsistent. Consistent
Backup taken when the database is mounted (but not in open),after proper shutdown.checkpoint SCNs in the datafile headers match the header information in the control file.
Inconsistent
A backup of any part of the target database when it is open or when a crash occurred or SHUTDOWN ABORT was run prior to mounting.An inconsistent backup requires recovery to become consistent.
Various backup using RMAN
Backing up Entire Database
rman target sys/sys@con_tar catalog cat/cat@con_cat RMAN>backup database;
( will backup data file , control file)
Backing up the archived logs
RMAN>backup archivedlog :
(will backup all archivedlog which haven’t backedup before) RMAN>backup database plus archivedlog ;
(Will backup data file+Archived log
)
Backing up control file :
RMAN>backup current controlfile; ( will backup current contolfile).
Backingup tablespace :
RMAN>backup tablespace <tbsname>;
(will backup tablespace DB should be in archivelogmode)
Backing datafile:
RMAN>backup datafile ‘<pathname>/<datafile name>’;
INCREMENTAL BACKUPS
• An incremental backup at level n, n > 0, copies only changed blocks since previous incremental backup whose level <= n
• Take a level 0 backup as base line for the succeeding incremental backups
• Can take multilevel incremental backup • Up to five levels of backups can be taken • Ex:
– Level 0 - Base line backup every month – Level 1 - Weekly incremental
– Level 2 - Daily incremental
• Cumulative incremental backup can be used to reduce recovery time
• Cumulative incremental backup at level n, n > 0, copies all changed blocks since previous incremental backup whose level <
n
• Incremental backup is useful when the database is very large • Cumulative incremental is useful to reduce database down time
during recovery
In a cumulative level 1 backup, RMAN backs up all the blocks used since the most recent level 0 incremental backup. Cumulative
incremental backups reduce the work needed for a restore by ensuring that you only need one incremental backup from any particular level. Cumulative backups require more space and time than differential backups, however, because they duplicate the work done by previous backups at the same level.
The following command performs a cumulative level 1 incremental backup of the database:
RMAN>BACKUP INCREMENTAL LEVEL 1 CUMULATIVE DATABASE;
Example of differential incremental backup
In a differential level 1 backup, RMAN backs up all blocks that have changed since the most recent cumulative or differental incremental backup, whether at level 1 or level 0. RMAN determines which level 1 backup occurred most recently and backs up all blocks modified after that backup. If no level 1 is available, RMAN copies all blocks changed since the level 0 backup.
The following command performs a level 1 differential incremental backup of the database:
RMAN> BACKUP INCREMENTAL LEVEL 1 differential DATABASE;
Recovery
Decide your scenario
Lost controlfile
Lost datafile
Lost entire database
Restore
• Restore database - Restores entire database including controlfile • Restore datafile <filename> - Restores specific datafiles
• Restore tablespace <tablespace_name> - Restores all datafiles belongs to tablespace.
• Restore controlfile - Restores only controlfile
• Restore archivelog all - Restores all archivelog files.
RECOVER
If restore completed successfully then following command
can be executed based on the recovery scenario.
– Recover database - Recovering entire database – Recover datafile <filename> - Recovering specific
datafiles
– recover tablespace <tablespace_name> - Recovering all datafiles belongs to the tablespace
– recover database until cancel - Recovering database until canel
– recover database until time = <TIME> - Until time – recover database until SCN = <SCN> - Until Specific
SCN
– recover database until SEQUENCE =<SEQ> - Until specific sequence
SQL> select file#, error, online_status, change#, time from v$recover_file;
SCENARIOS
Scenario 1 Recover full database
Need to recover full database including controlfile, If we have backup then we can start recovery.
Rman
RMAN > Connect target sys/sys@con_tar RMAN > connect catalog cat/cat@con_cat RMAN > startup nomount
RMAN > run {
restore database; alter database mount; recover database; }
Scenario 2 Recover Lost controlfile
•
Target database Shut abort
Startup nomount
• Connect to rman catalog and target database RMAN > run
{
Restore controlfile; alter database mount; recover database;
alter database open resetlogs; }
Scenario 3 Recover lost datafile
RMAN> RUN
{alter tablespace sysaux offline; restore datafile
‘/home/oracle10g/data/sysaux1.dbf'; recover datafile
‘/home/oracle10g/data/sysaux1.dbf'; alter tablespace sysaux online
}
Scenario 4 Recover lost tablespace
RMAN>run {
alter tablespace sysaux offline restore tablespace sysaux recover tablespace sysaux alter tablespace sysaux online }
