USING THE DATA RECOVERY ADVISOR (DRA)

The DRA is a new tool introduced in oracle 11G, that automatically diagnose database failures and determines the appropriate recovery options. in addition, it can perform the recovery after the DBA confirms the operation. DRA can proactively check for failures, before the database process detects corruption and signals an error.

DRA may be used with Em or RMAN command line. DRA supports only single -instance databases(no RAC environments ).

Support workbench tool is invoked from the software and support tab of the EM, and shows the failures in the Database . when you clicking the launch recovery advisor button, you can invoke DRA.

The health monitor (Hm) tool in the oracle 11G proactively monitors the health of the database . it assesses data failures and reports to the DRA , that assigns the priority based on the failure.

failure chcks in the database(DB) can be reactive or proactive. when an error occurs in the db , reactive checks are automatically executed. the following are examples of data failures where the Dra suggest reapir options:

- Missing or corrupted datafiles

- datafiles with incorrect OS permissions

- offline tablespaces

- corrupt index entry or dictinonary entry

- i/o failures

- number of open files exceeded

RECUPERANDO BD EN ORACLE - cuando pierdes UN control file(resumen sybex)

Losing one of the multiplexed control file immediately aborts the instance.

1- shutdown abort

2- copy one of the good copies of the control file to the location of the corrupted or missings control file.

if the corrupted Cfile resided on a failed disk , copy it to another suitable location and update the initialization parameter to update the cfile reference or you can remove the reference from this initialization parameter until you find a suitable location.

you must have at least two control files in your Db.

3-start the instance with startup.

you´ll change the initialization parameter control_file using the alter system set scope=spfile when the instance is started in no mount mode.