Thursday, December 23, 2010

Recovering unmountable Oracle 9i database

The instance of an Oracle server is assembled using allocated memory (System Global Area) and running process (SMON, PMON, LGWR, DBWR). When you start the Server instance, it is allocated with the particular database, which is known as the mounting the Oracle database. This is the most primitive step of using the database and its related records. However, at times you are unable to access the Oracle instance. Such problems may occur due to corruption in Oracle database, which can happen because of various reasons such as media block corruption, damaged file system, damage in the Oracle 9i application server, etc. In such cases, you should try out each and every possible workaround to recover Oracle database including using latest database backup. If you are unable to fix the error, then you should use a third-party Oracle database recovery software to do the needful.

Consider a scenario wherein you are having Oracle 9i server on your Windows Server 2003 system. You try to mount the Oracle database using the following command:

oradim -new -sid %ORACLE_SID% -pfile c:xyz.ora

However, you are unable to mount the database instance. An erro message is displayed suggesting that the database cannot be mounted.

Cause:

There could be the following causes for the aforementioned problem:

You may not have the appropriate credentials to log into the database server and mount the database.
You are unable to open the parameter file.
The database has corrupted due to any of the reasons mentioned earlier in this article.

Resolution:

To resolve this problem, you need to repair Oracle database. To do this, you would have to ensure the following precautions:

You have the appropriate credentials to log into the database server.
The parameter file is at its mentioned location.
Try to find out if the backup of the database is clean and updated. If yes, then you should restore the database with its backup.
You should use the DBMS_REPAIR method to repair the block corruption in the Oracle database.

However, if you are still not able to mount the Oracle database then you should use a third-party DBF recovery software. Such read-only tools are able to recover DBF files without overwriting the existing database.

Stellar Phoenix Oracle Database Recovery is an Oracle database recovery software that repairs Oracle database created in Oracle 9i. It is capable of recovering various database components such as tables, views, cluster tables, schemas, sequences, etc. In addition, this oracle recovery software restores primary and foreign keys associated with the database tables. It is compatible with Windows Server 2003 and XP.

Resource: http://www.americanchronicle.com/articles/view/204324

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