Backup & Recovery Scenarios

Backup & Recovery Scenarios

User Managed Recovery Scenarios And Configuration
1. Complete Closed Database Recovery. System tablespace is missing
2. Complete Open Database Recovery. Non system tablespace is missing
3. Complete Open Database Recovery (when the database is initially closed). Non system tablespace is missing
4. Recovery of a Missing Datafile that has no backups.
5. Restore and Recovery of a Datafile to a different location.
6. Control File Recovery
7. Incomplete Recovery, Until Time/Sequence/Cancel
RMAN Recovery Scenarios And Configuration
1. Complete Closed Database Recovery. System tablespace is missing
2. Complete Open Database Recovery. Non system tablespace is missing
3. Complete Open Database Recovery (when the database is initially closed). Non system tablespace is missing
4. Recovery of a Datafile that has no backups.
5. Restore and Recovery of a Datafile to a different location.
6. Control File Recovery
7. Incomplete Recovery, Until Time/Sequence/Cancel
User Managed Recovery Scenarios
User managed recovery scenarios do require that the database is in archive log mode, and that backups of all datafiles and control files are made with the tablespaces set to begin backup, if the database is open while the copy is made. At the end of the copy of each tablespace it is necessaire to take it out of backup mode. Alternatively complete backups can be made with the database shutdown. Online redologs can be optionally backed up. Files to be copied: select name from v$datafile;
select member from v$logfile; # optional select name from v$controlfile;
Complete Closed Database Recovery. System tablespace is missing
If the system tablespace is missing or corrupted the database cannot be started up so a complete closed database recovery must be performed. Pre requisites: A closed or open database backup and archived logs.
1. Use OS commands to restore the missing or corrupted system datafile to its original location, ie: cp -p /user/backup/uman/system01.dbf /user/oradata/u01/dbtst/system01.dbf
2. startup mount;
3. recover datafile 1;
4. alter database open;

Complete Open Database Recovery. Non system tablespace is missing
If a non system tablespace is missing or corrupted while the database is open, recovery can be performed while the database remain open. Pre requisites: A closed or open database backup and archived logs.
1. Use OS commands to restore the missing or corrupted datafile to its original location, ie: cp -p /user/backup/uman/user01.dbf /user/oradata/u01/dbtst/user01.dbf
2. alter tablespace <tablespace_name> offline immediate;
3. recover tablespace <tablespace_name>;
4. alter tablespace <tablespace_name> online;

Complete Open Database Recovery (when the database is initially closed). Non system tablespace is missing
If a non system tablespace is missing or corrupted and the database crashed, recovery can be performed after the database is open. Pre requisites: A closed or open database backup and archived logs.
1. startup; (you will get ora-1157 ora-1110 and the name of the missing datafile, the database will remain mounted)
2. Use OS commands to restore the missing or corrupted datafile to its original location, ie: cp -p /user/backup/uman/user01.dbf /user/oradata/u01/dbtst/user01.dbf
3. alter database datafile3 offline; (tablespace cannot be used because the database is not open)
4. alter database open;
5. recover datafile 3;
6. alter tablespace <tablespace_name> online;

Recovery of a Missing Datafile that has no backups (database is open).
If a non system datafile that was not backed up since the last backup is missing, recovery can be performed if all archived logs since the creation of the missing datafile exist. Pre requisites: All relevant archived logs.
1. alter tablespace <tablespace_name> offline immediate;
2. alter database create datafile ‘/user/oradata/u01/dbtst/newdata01.dbf’;
3. recover tablespace <tablespace_name>;
4. alter tablespace <tablespace_name> online;
If the create datafile command needs to be executed to place the datafile on a location different than the original use:
alter database create datafile ‘/user/oradata/u01/dbtst/newdata01.dbf’ as ‘/user/oradata/u02/dbtst/newdata01.dbf’

Restore and Recovery of a Datafile to a different location.
If a non system datafile is missing and its original location not available, restore can be made to a different location and recovery performed. Pre requisites: All relevant archived logs.
1. Use OS commands to restore the missing or corrupted datafile to the new location, ie: cp -p /user/backup/uman/user01.dbf /user/oradata/u02/dbtst/user01.dbf
2. alter tablespace <tablespace_name> offline immediate;
3. alter tablespace <tablespace_name> rename datafile ‘/user/oradata/u01/dbtst/user01.dbf’ to ‘/user/oradata/u02/dbtst/user01.dbf’;
4. recover tablespace <tablespace_name>;
5. alter tablespace <tablespace_name> online;

Control File Recovery
Always multiplex your controlfiles. Controlfiles are missing, database crash. Pre requisites: A backup of your controlfile and all relevant archived logs.
1. startup; (you get ora-205, missing controlfile, instance start but database is not mounted)
2. Use OS commands to restore the missing controlfile to its original location: cp -p /user/backup/uman/control01.dbf /user/oradata/u01/dbtst/control01.dbf cp -p /user/backup/uman/control02.dbf /user/oradata/u01/dbtst/control02.dbf
3. alter database mount;
4. recover automatic database using backup controlfile;
5. alter database open resetlogs;
6. make a new complete backup, as the database is open in a new incarnation and previous archived log are not relevant.

Incomplete Recovery, Until Time/Sequence/Cancel
Incomplete recovery may be necessaire when an archived log is missing, so recovery can only be made until the previous sequence, or when an important object was dropped, and recovery needs to be made until before the object was dropped. Pre requisites: A closed or open database backup and archived logs, the time or sequence that the ‘until’ recovery needs to be performed.
1. If the database is open, shutdown abort
2. Use OS commands to restore all datafiles to its original locations: cp -p /user/backup/uman/u01/*.dbf /user/oradata/u01/dbtst/ cp -p /user/backup/uman/u02/*.dbf /user/oradata/u01/dbtst/ cp -p /user/backup/uman/u03/*.dbf /user/oradata/u01/dbtst/ cp -p /user/backup/uman/u04/*.dbf /user/oradata/u01/dbtst/ etc…
3. startup mount;
4. recover automatic database until time ‘2004-03-31:14:40:45′;
5. alter database open resetlogs;
6. make a new complete backup, as the database is open in a new incarnation and previous archived log are not relevant.
Alternatively you may use instead of until time, until sequence or until cancel:
recover automatic database until sequence 120 thread 1; OR recover database until cancel;

Rman Recovery Scenarios
Rman recovery scenarios require that the database is in archive log mode, and that backups of datafiles, control files and archived redolog files are made using Rman. Incremental Rman backups may be used also. Rman can be used with the repository installed on the archivelog, or with a recovery catalog that may be installed in the same or other database. Configuration and operation recommendations:
Set the parameter controlfile autobackup to ON to have with each backup a controlfile backup also:
configure controlfile autobackup on;
Set the parameter retention policy to the recovery window you want to have, ie redundancy 2 will keep the last two backups
available, after executing delete obsolete commands:
configure retention policy to redundancy 2;
Execute your full backups with the option ‘plus archivelogs’ to include your archivelogs with every backup:
backup database plus archivelog;
Perform daily maintenance routines to maintain on your backup directory the number of backups you need only:
crosscheck backup;
crosscheck archivelog all;
delete noprompt obsolete backup;
To work with Rman and a database based catalog follow these steps:
1. sqlplus /
2. create tablespace repcat;
3. create user rcuser identified by rcuser default tablespace repcat temporary tablespace temp;
4. grant connect, resource, recovery_catalog_owner to rcuser
5. exit
6. rman catalog rcuser/rcuser # connect to rman catalog as the rcuser
7. create catalog # create the catalog
8. connect target / #

Complete Closed Database Recovery. System tablespace is missing
In this case complete recovery is performed, only the system tablespace is missing, so the database can be opened without reseting the redologs.
1. rman target /
2. startup mount;
3. restore database;
4. recover database;
5. alter database open;

Complete Open Database Recovery. Non system tablespace is missing, database is up
1. rman target /
2. sql ‘alter tablespace <tablespace_name> offline immediate’;
3. restore datafile 3;
4. recover datafile 3;
5. sql ‘alter tablespace <tablespace_name> online’;

Complete Open Database Recovery (when the database is initially closed). Non system tablespace is missing
A user datafile is reported missing when tryin to startup the database. The datafile can be turned offline and the database started up. Restore and recovery are performed using Rman. After recovery is performed the datafile can be turned online again.
1. sqlplus /nolog
2. connect / as sysdba
3. startup mount
4. alter database datafile ‘<datafile_name>’ offline;
5. alter database open;
6. exit;
7. rman target /
8. restore datafile ‘<datafile_name>’;
9. recover datafile ‘<datafile_name>’;
10. sql ‘alter tablespace <tablespace_name> online’;

Recovery of a Datafile that has no backups (database is up).
If a non system datafile that was not backed up since the last backup is missing, recovery can be performed if all archived logs since the creation of the missing datafile exist. Since the database is up you can check the tablespace
name and put it offline. The option offline immediate is used to avoid that the update of the datafile header. Pre requisites: All relevant archived logs.
1. sqlplus ‘/ as sysdba’
2. alter tablespace <tablespace_name> offline immediate;
3. alter database create datafile ‘/user/oradata/u01/dbtst/newdata01.dbf;
4. exit
5. rman target /
6. recover tablespace <tablespace_name>;
7. sql ‘alter tablespace <tablespace_name> online’;
If the create datafile command needs to be executed to place the datafile on a location different than the original use:
alter database create datafile ‘/user/oradata/u01/dbtst/newdata01.dbf’ as ‘/user/oradata/u02/dbtst/newdata01.dbf’

Restore and Recovery of a Datafile to a different location. Database is up.
If a non system datafile is missing and its original location not available, restore can be made to a different location and recovery performed. Pre requisites: All relevant archived logs, complete cold or hot backup.
1. Use OS commands to restore the missing or corrupted datafile to the new location, ie: cp -p /user/backup/uman/user01.dbf /user/oradata/u02/dbtst/user01.dbf
2. alter tablespace <tablespace_name> offline immediate;
3. alter tablespace <tablespace_name> rename datafile ‘/user/oradata/u01/dbtst/user01.dbf’ to ‘/user/oradata/u02/dbtst/user01.dbf’;
4. rman target /
5. recover tablespace <tablespace_name>;
6. sql ‘alter tablespace <tablespace_name> online’;

Control File Recovery
Always multiplex your controlfiles. If you loose only one controlfile you can replace it with the one you have in place, and startup the Database. If both controlfiles are missing, the database will crash. Pre requisites: A backup of your controlfile and all relevant archived logs. When using Rman alway set configuration parameter autobackup of controlfile to ON. You will need the dbid to restore the controlfile, get it from the name of the backed up controlfile. It is the number following the ‘c-‘ at the start of the name.
1. rman target /
2. set dbid <dbid#>
3. startup nomount;
4. restore controlfile from autobackup;
5. alter database mount;
6. recover database;
7. alter database open resetlogs;
8. make a new complete backup, as the database is open in a new incarnation and previous archived log are not relevant.

Incomplete Recovery, Until Time/Sequence/Cancel
Incomplete recovery may be necessaire when the database crash and needs to be recovered, and in the recovery process you find that an archived log is missing. In this case recovery can only be made until the sequence before the one that is missing. Another scenario for incomplete recovery occurs when an important object was dropped or incorrect data was committed on it. In this case recovery needs to be performed until before the object was dropped. Pre requisites: A full closed or open database backup and archived logs, the time or sequence that the ‘until’ recovery needs to be performed.
1. If the database is open, shutdown it to perform full restore.
2. rman target \
3. startup mount;
4. restore database;
5. recover database until sequence 8 thread 1; # you must pass the thread, if a single instance will always be 1.
6. alter database open resetlogs;
7. make a new complete backup, as the database is open in a new incarnation and previous archived log are not relevant.
Alternatively you may use instead of until sequence, until time, ie: ‘2004-12-28:01:01:10′.

Up To Time Based Recovery In RMAN

April 28, 2010

Point in time recovery using RMAN (until a log sequence number)

Recovery Objective

SQL> conn scott/tiger

Connected.

SQL> select count(*) from myobjects;

COUNT(*)

———-

249410

Switch a logfile

SQL> conn / as sysdba

Connected.

SQL> alter system switch logfile;

System altered.

Note the current log sequence number (13)

SQL> archive log list

Database log mode              Archive Mode

Automatic archival             Enabled

Archive destination            /u02/ORACLE/opsdba/arch

Oldest online log sequence     12

Next log sequence to archive   14

Current log sequence           14

Simulate an application failure – WRONG Delete!!

SQL> conn scott/tiger

Connected.

SQL> delete myobjects;

249410 rows deleted.

SQL> commit;

Commit complete.

The developer states that the wrong DML statement was made AFTER 8.15 AM and is positive about the same.

We need to determine the log sequence we need to recover until

select sequence#,first_change#, to_char(first_time,’HH24:MI:SS’) from v$log order by 3

SQL> /

SEQUENCE# FIRST_CHANGE# TO_CHAR(

———- ————- ——–

13       2760463 07:49:36

14       2761178 08:12:47

15       2766622 08:18:49

Log sequence 14 was first written to at 8:12 AM so we should recover to a log sequence before this – i.e sequence# 13

Shutdown and mount the database

SQL> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup mount;

ORACLE instance started.

Total System Global Area  264241152 bytes

Fixed Size                  2070416 bytes

Variable Size             163580016 bytes

Database Buffers           92274688 bytes

Redo Buffers                6316032 bytes

Database mounted.

RMAN> run {

2> set until sequence=14;  >>> add one to the sequence number we have to recover until

3> restore database;

4> recover database;

5> }

executing command: SET until clause

Starting restore at 29-JAN-07

allocated channel: ORA_DISK_1

channel ORA_DISK_1: sid=154 devtype=DISK

allocated channel: ORA_SBT_TAPE_1

channel ORA_SBT_TAPE_1: sid=158 devtype=SBT_TAPE

channel ORA_SBT_TAPE_1: Data Protection for Oracle: version 5.2.4.0

channel ORA_DISK_1: starting datafile backupset restore

channel ORA_DISK_1: specifying datafile(s) to restore from backup set

restoring datafile 00001 to /u02/ORACLE/opsdba/system01.dbf

restoring datafile 00002 to /u02/ORACLE/opsdba/undotbs01.dbf

restoring datafile 00003 to /u02/ORACLE/opsdba/sysaux01.dbf

restoring datafile 00004 to /u02/ORACLE/opsdba/users01.dbf

restoring datafile 00005 to /u02/ORACLE/opsdba/users02.dbf

restoring datafile 00006 to /u02/ORACLE/opsdba/users03.dbf

restoring datafile 00007 to /u02/ORACLE/opsdba/users05.dbf

restoring datafile 00008 to /u02/ORACLE/opsdba/users06.dbf

restoring datafile 00009 to /u02/ORACLE/opsdba/users07.dbf

restoring datafile 00010 to /u02/ORACLE/opsdba/users04.dbf

restoring datafile 00011 to /u02/ORACLE/opsdba/drtbs1.dbf

restoring datafile 00012 to /u02/ORACLE/opsdba/drtbs2.dbf

channel ORA_DISK_1: reading from backup piece /opt/oracle/backup/opsdba/OPSDBA.20070129.161.1.1.613122551

channel ORA_DISK_1: restored backup piece 1

piece handle=/opt/oracle/backup/opsdba/OPSDBA.20070129.161.1.1.613122551 tag=TAG20070129T074911

channel ORA_DISK_1: restore complete, elapsed time: 00:00:16

Finished restore at 29-JAN-07

Starting recover at 29-JAN-07

using channel ORA_DISK_1

using channel ORA_SBT_TAPE_1

starting media recovery

archive log thread 1 sequence 13 is already on disk as file /u02/ORACLE/opsdba/arch/arch_1_13_613052894.dbf

channel ORA_DISK_1: starting archive log restore to default destination

channel ORA_DISK_1: restoring archive log

archive log thread=1 sequence=12

channel ORA_DISK_1: reading from backup piece /opt/oracle/backup/opsdba/OPSDBA.20070129.162.1.1.613122577

channel ORA_DISK_1: restored backup piece 1

piece handle=/opt/oracle/backup/opsdba/OPSDBA.20070129.162.1.1.613122577 tag=TAG20070129T074937

channel ORA_DISK_1: restore complete, elapsed time: 00:00:02

archive log filename=/u02/ORACLE/opsdba/arch/arch_1_12_613052894.dbf thread=1 sequence=12

archive log filename=/u02/ORACLE/opsdba/arch/arch_1_13_613052894.dbf thread=1 sequence=13

media recovery complete, elapsed time: 00:00:01

Finished recover at 29-JAN-07

RMAN> sql ‘alter database open resetlogs’;

sql statement: alter database open resetlogs

Confirm that the recovery has worked

opsdba:/opt/tivoli/tsm/client/oracle/bin64>sqlplus scott/tiger

SQL*Plus: Release 10.2.0.2.0 – Production on Mon Jan 29 09:43:14 2007

Copyright (c) 1982, 2005, Oracle.  All Rights Reserved.

Connected to:

Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 – 64bit Production

With the Partitioning, Oracle Label Security, OLAP and Data Mining options

SQL> select count(*) from myobjects;

COUNT(*)

———-

249410

Controlfile Recover

April 28, 2010

SCENARIO – LOSS OF ALL CONTROLFILES (NO CATALOG)

SQL> insert into myobjects select * from myobjects;

919664 rows created.

SQL> commit;

Commit complete.

SQL> select count(*) from myobjects;

COUNT(*)

———-

1839328 >>>> need to check this record count after recovery

SQL> archive log list

Database log mode              Archive Mode

Automatic archival             Enabled

Archive destination            USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence     5

Next log sequence to archive   7

Current log sequence           7

Note – current log sequence is 7 – not archived but contains the last committed changes that we made

Note – archive logs will not be found in $ARCV area, but in the flashback location

Simulate a failure

SQL> select name from v$controlfile;

NAME

——————————————————————————–

/u01/ORACLE/testdb/control01.ctl

/u01/ORACLE/testdb/control02.ctl

/u01/ORACLE/testdb/control03.ctl

SQL> !rm /u01/ORACLE/testdb/*.ctl

SQL> alter tablespace users online;

alter tablespace users online

*

ERROR at line 1:

ORA-00603: ORACLE server session terminated by fatal error

SQL> shutdown abort

ORACLE instance shut down.

SQL> startup nomount;

ORACLE instance started.

Total System Global Area  893386752 bytes

Fixed Size                  2076816 bytes

Variable Size             432017264 bytes

Database Buffers          452984832 bytes

Redo Buffers                6307840 bytes

Since we are not using a RMAN catalog we need to set the DBID

RMAN> set dbid=2415549446;

executing command: SET DBID

Restore the controlfile

RMAN> run {

2> restore controlfile from autobackup;

3> }

Starting restore at 10-JAN-10

using target database control file instead of recovery catalog

allocated channel: ORA_DISK_1

channel ORA_DISK_1: sid=156 devtype=DISK

recovery area destination: /u01/ORACLE/flash_recovery_area

database name (or database unique name) used for search: TESTDB

channel ORA_DISK_1: autobackup found in the recovery area

channel ORA_DISK_1: autobackup found: /u01/ORACLE/flash_recovery_area/TESTDB/autobackup/2010-01-10/o1_mf_s_633601094_3gynd74g_.bkp

channel ORA_DISK_1: control file restore from autobackup complete

output filename=/u01/ORACLE/testdb/control01.ctl

output filename=/u01/ORACLE/testdb/control02.ctl

output filename=/u01/ORACLE/testdb/control03.ctl

Finished restore at 10-JAN-10

Mount and recover the database

RMAN> alter database mount;

database mounted

released channel: ORA_DISK_1

RMAN> recover database;

Starting recover at 10-JAN-10

Starting implicit crosscheck backup at 10-JAN-10

allocated channel: ORA_DISK_1

channel ORA_DISK_1: sid=156 devtype=DISK

Crosschecked 1 objects

Finished implicit crosscheck backup at 10-JAN-10

Starting implicit crosscheck copy at 10-JAN-10

using channel ORA_DISK_1

Finished implicit crosscheck copy at 10-JAN-10

searching for all files in the recovery area

cataloging files…

cataloging done

List of Cataloged Files

=======================

File Name: /u01/ORACLE/flash_recovery_area/TESTDB/autobackup/2010-01-10/o1_mf_s_633601094_3gynd74g_.bkp

using channel ORA_DISK_1

allocated channel: ORA_SBT_TAPE_1

channel ORA_SBT_TAPE_1: sid=155 devtype=SBT_TAPE

channel ORA_SBT_TAPE_1: Data Protection for Oracle: version 5.2.4.0

datafile 4 not processed because file is offline

starting media recovery

archive log thread 1 sequence 6 is already on disk as file /u01/ORACLE/flash_recovery_area/TESTDB/archivelog/2010-01-10/o1_mf_1_6_3gyn7vnk_.arc

archive log thread 1 sequence 7 is already on disk as file /u01/ORACLE/testdb/redo03.log

archive log filename=/u01/ORACLE/flash_recovery_area/TESTDB/archivelog/2010-01-10/o1_mf_1_6_3gyn7vnk_.arc thread=1 sequence=6

archive log filename=/u01/ORACLE/testdb/redo03.log thread=1 sequence=7  >>>> current redo log with committed but unarchived changes applied

media recovery complete, elapsed time: 00:00:09

Finished recover at 10-JAN-10

SQL> alter database open resetlogs;

Database altered.

conn scott/tiger

Connected.

SQL> select count(*) from myobjects;

COUNT(*)

———-

1839328

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