Laurent Schneider

You will probably not hit this bug unless you perform some media recovery in 11.2.0.1/AIX.

Ok. In case you hit ORA-10878: parallel recovery slave died unexpectedly during a DUPLICATE or a RESTORE command, you can disable parallel media recovery with _log_parallelism_max=1.

The usual warning applies : do not use hidden parameter without guidance of Oracle Support. Open an SR if you hit this bug. Check for a patch on your plateform. Read notes 9728806.8 and 315631.1.

Note: for a RECOVER, the option RECOVER NOPARALLEL must be safer. Unfortunately there is no such thing like DUPLICATE NOPARALLEL

I had a very serious issue last Friday with errors as weird as ORA-00322: log name of thread num is not current copy. After a clone from Prod to Test, the prod crashed. Both databases are located on the same server (I am not a virtualization fanatic) and clone from prod to test have been done by most of my dba readers.

What did change in 11g ?

Incredibly, in 11g, rman issues the following statement before restore

sql clone "alter system set  db_name = ''PROD'' ...
restore clone primary controlfile...

This is probably related to the capability of cloning a database without connecting to the target database.

At the end of the clone, rman is setting back the db_name to TEST and recreate the TEST controlfile

sql statement: alter system set  db_name = ''TEST'' ...
sql statement: CREATE CONTROLFILE REUSE SET DATABASE "TEST" ...
...
LOGFILE
GROUP 1 ('/.../TEST/redo1.dbf')...

So what’s wrong with this? Howcome could a clone from prod to test screw up the prod db???

Simple, the RMAN job did not complete

1) set new name, restore prod controlfile to test
2) restore issue, for instance ORA-19870: error while restoring backup piece archive1234
3) RMAN-03002: failure of Duplicate Db command

At this point, the complete restore was finished, we restored the missing archivelog, recover and open resetlog.
What happened then???
At this point, remember you still have the prod controlfile (and the prod db_name), so by doing an alter resetlogs, the production redologs will get overwritten without notice !

This is a fairly important change that could really hurt if you are cloning two databases on the same server.

In case you are trying to save a failed database clone, make sure you check db_name and also v$logfile before doing an alter database resetlogs!!!

If you want to keep some backups forever, you maybe tried

RMAN> backup database keep forever logs;

Starting backup at 13.04.2007 13:58:04
...
backup will never be obsolete
archived logs required to recover from this backup 
will expire when this backup expires
...
Finished backup at 13.04.2007 13:58:23

but the problem is that the archivelogs to recover this backup at any time after the backup will NEVER be obsolete.

You could well try the NOLOGS option, but this requires you to take the database in the MOUNT state.

RMAN> backup database keep forever nologs;

Starting backup at 13.04.2007 14:06:36
...
backup will never be obsolete
archived logs required to recover from this backup 
will not be kept
...
Finished backup at 13.04.2007 14:07:25

This is fine if you can stop your database. But you probably wants online backup. What’s next?

Ok, here is the way to go. You do your online backup, then you mark what you want to keep !

First I backup the old archivelogs, because I do not need to keep those yet.

RMAN> backup archivelog all;

Starting backup at 13.04.2007 14:10:00
...
Finished backup at 13.04.2007 14:10:08

Now I do a backup plus archivelog (with a tag for simplicity)

RMAN> backup database tag backuplsc 
plus archivelog tag backuplsc;

Starting backup at 13.04.2007 14:10:42
...
Finished backup at 13.04.2007 14:11:00

Now I can mark my backup as keep

RMAN> change backup tag backuplsc keep forever;

...
keep attributes for the backup are changed
backup will never be obsolete
backup set key=405 RECID=116 STAMP=619798257
keep attributes for the backup are changed
backup will never be obsolete
backup set key=406 RECID=117 STAMP=619798260

Now if I do a delete obsolete, it will never delete my backup.

RMAN> backup database plus archivelog
Starting backup at 13.04.2007 14:16:46
...
Finished backup at 13.04.2007 14:17:10

RMAN> delete noprompt obsolete;

RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 1
...
Deleting the following obsolete backups and copies:
...
Deleted 7 objects

RMAN> list backup summary;

List of Backups
===============
Key     TY LV S Device Type Completion Time    
------- -- -- - ----------- ------------------- 
 #Pieces #Copies Compressed Tag
------- ------- ---------- ---
...
405     B  F  A DISK        13.04.2007 14:10:57 
1       1       YES        BACKUPLSC
406     B  F  A DISK        13.04.2007 14:11:00 
1       1       YES        BACKUPLSC
...