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1.
Cumulative Backup Overview
Sometimes
we need to backup the database changes only from the last backup (only
the last changes are backed up). This is an incremental backup. There
are 2 types of incremental backup: DIFFERENTIAL (by default) &
CUMULATIVE.
NOTE:
The incremental backups are only for the DATA files.
CUMULATIVE
backup = which backs up all blocks changed after the
most recent incremental backup at level 0. See the picture bellow.
The
following RMAN command is used to take a CUMULATIVE database backup:
RMAN>
BACKUP INCREMENTAL LEVEL 1 CUMULATIVE DATABASE;
2.
Cumulative Restore Overview
Because
a CUMULATIVE backup is taken each day during the week, we need to
restore 2 times: 1st we have to restore the full backup and after that
the last cumulative backup (for a complete restore). If differential
backups are taken we have to restore all the differential backups until
the database crash.
3.
Taking a full backup (supposing on Sunday at 1 am) - level 0
A
database backup is taken using the following RMAN script (which is
stored in the /home/oracle/Desktop/Backup_rman/scripts/hot_database_backup_disk.sh
file):
#/usr/bin/ksh
export ORACLE_HOME=/DB1
export ORACLE_SID=db1
RMAN_LOG_FILE=/home/oracle/Desktop/Backup_rman/log/hot_database_backup.`date
+%y%m%d%H%M`.out
# -----------------------------------------------------------------
# Initialize the log file.
# -----------------------------------------------------------------
echo>> $RMAN_LOG_FILE
chmod 666 $RMAN_LOG_FILE
echo Script $0>> $RMAN_LOG_FILE
echo ==== started on `date` ====>> $RMAN_LOG_FILE
echo>> $RMAN_LOG_FILE
ORACLE_USER=oracle
TARGET_CONNECT_STR=sys/s
RMAN=$ORACLE_HOME/bin/rman
BACKUP_TYPE="INCREMENTAL LEVEL 0"
#
---------------------------------------------------------------------------
# Print out the value of the variables set by this script.
#
---------------------------------------------------------------------------
echo>> $RMAN_LOG_FILE
echo "RMAN: $RMAN">> $RMAN_LOG_FILE
echo "ORACLE_SID: $ORACLE_SID">> $RMAN_LOG_FILE
echo "ORACLE_USER: $ORACLE_USER">> $RMAN_LOG_FILE
echo "ORACLE_HOME: $ORACLE_HOME">> $RMAN_LOG_FILE
echo "BACKUP_TYPE: $BACKUP_TYPE">> $RMAN_LOG_FILE
#
---------------------------------------------------------------------------
echo >> $RMAN_LOG_FILE
CMD_STR=""
$RMAN target $TARGET_CONNECT_STR catalog rman/r@dbr << EOF
RUN {
ALLOCATE CHANNEL ch00 TYPE disk ;
ALLOCATE CHANNEL ch01 TYPE disk ;
ALLOCATE CHANNEL ch02 TYPE disk ;
ALLOCATE CHANNEL ch03 TYPE disk ;
BACKUP
$BACKUP_TYPE
SKIP INACCESSIBLE
TAG hot_db_bk_level0
FILESPERSET 5
# recommended format
FORMAT '/home/oracle/Desktop/Backup_rman/backup/bk_%s_%p_%t'
DATABASE;
sql 'alter system archive log current';
RELEASE CHANNEL ch00;
RELEASE CHANNEL ch01;
RELEASE CHANNEL ch02;
RELEASE CHANNEL ch03;
# backup all archive logs
ALLOCATE CHANNEL ch00 TYPE disk;
ALLOCATE CHANNEL ch01 TYPE disk;
BACKUP
SKIP INACCESSIBLE
filesperset 20
FORMAT '/home/oracle/Desktop/Backup_rman/backup/al_%s_%p_%t'
ARCHIVELOG ALL DELETE INPUT;
RELEASE CHANNEL ch00;
RELEASE CHANNEL ch01;
ALLOCATE CHANNEL ch00 TYPE disk;
BACKUP
# recommended format
FORMAT '/home/oracle/Desktop/Backup_rman/backup/cntrl_%s_%p_%t'
CURRENT CONTROLFILE;
RELEASE CHANNEL ch00;
}
EOF
NOTE:
The database must be in archivelog mode.
4.
Taking a cumulative backup (supposing on Monday at 1 am) - level
1
A
cumulative backup is taken using the following script
[oracle@PROD scripts]$ more
cumulative_database_backup_disk.sh
#/usr/bin/ksh
ORACLE_HOME=/DB1
export ORACLE_HOME
ORACLE_SID=db1
export ORACLE_SID
RMAN_LOG_FILE=/home/oracle/Desktop/Backup_rman/log/cumulative_day_level1.`date +%y%m%d%H%M`.out
echo >> $RMAN_LOG_FILE
chmod 666 $RMAN_LOG_FILE
echo Script $0 >> $RMAN_LOG_FILE
echo ==== started on `date` ==== >> $RMAN_LOG_FILE
echo >> $RMAN_LOG_FILE
ORACLE_USER=oracle
TARGET_CONNECT_STR=sys/s
RMAN=$ORACLE_HOME/bin/rman
BACKUP_TYPE="INCREMENTAL LEVEL 1 CUMULATIVE"
echo >> $RMAN_LOG_FILE
echo "RMAN: $RMAN" >> $RMAN_LOG_FILE
echo "ORACLE_SID: $ORACLE_SID" >> $RMAN_LOG_FILE
echo "ORACLE_USER: $ORACLE_USER" >> $RMAN_LOG_FILE
echo "ORACLE_HOME: $ORACLE_HOME" >> $RMAN_LOG_FILE
echo "BACKUP_TYPE: $BACKUP_TYPE" >> $RMAN_LOG_FILE
echo >> $RMAN_LOG_FILE
CMD_STR=""
$RMAN target $TARGET_CONNECT_STR catalog rman/r@dbr << EOF
RUN {
ALLOCATE CHANNEL ch00 TYPE disk ;
BACKUP
$BACKUP_TYPE
SKIP INACCESSIBLE
TAG day_bk_cumulative1
FILESPERSET 5
# recommended format
FORMAT '/home/oracle/Desktop/Backup_rman/backup/cumulative_bk_%s_%p_%t'
DATABASE;
RELEASE CHANNEL ch00;
ALLOCATE CHANNEL ch00 TYPE disk;
BACKUP
# recommended format
FORMAT '/home/oracle/Desktop/Backup_rman/backup/cntrl_%s_%p_%t_inc'
CURRENT CONTROLFILE;
RELEASE CHANNEL ch00;
}
EOF
5.
Taking a cumulative backup (supposing on Tuesday at 1 am) - level
1
The
same script (from 4. ) is used for another cumulative backup on
Tuesday at 1 am.
6.
Simulate a disk crash on Tuesday at noon
Now
delete a datafile, /DB1/oradata/db1/users01.dbf for instance,
SHUTDOWN the database using ABORT option and restart the database.
The
following message will appear:
More information
about this subject (
Recovering a file using a cumulative backup ( with RMAN ) ) you can get from
www.in-oracle.com
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