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:
rman>configure controlfile autobackup on;
Set the parameter retention policy to the recovery
window you want to have, i.e redundancy 2 will keep
the last two backups available, after executing
delete obsolete commands:
rman>configure retention policy to redundancy 2;
Execute your full backups with the option
'plus archivelogs' to include your
archivelogs with every backup:
rman>backup database plus archivelog;
Perform daily maintenance routines to maintain on
your backup directory the number of backups you need only:
rman>crosscheck backup;
rman>crosscheck archivelog all;
rman>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
3. restore datafile 3;
4. recover datafile 3;
5. sql 'alter tablespace
=============================================
Complete Open Database Recovery (when the database
is initially closed). Non system tablespace is missing
---------------------------------------------
A user datafile is reported missing when trying 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 '
5. alter database open;
6. exit;
7. rman target /
8. restore datafile '
9. recover datafile '
10. sql 'alter tablespace
=============================================
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
3. alter database create datafile '/user/oradata/u01/dbtst/newdata01.dbf;
4. exit
5. rman target /
6. recover tablespace
7. sql 'alter tablespace
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
3. alter tablespace
'/user/oradata/u01/dbtst/user01.dbf' to '/user/oradata/u02/dbtst/user01.dbf';
4. rman target /
5. recover tablespace
6. sql 'alter tablespace
=============================================
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
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 orsequence 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: '2008-03-
16:01:01:10'.
No comments:
Post a Comment