RMAN-Backup and Recovery : part - 2 (Loss of Control File) ! ** The Most Essential But The Most Ignored **

Loss of Control File :

•CF1: Loosing one of the Multiplexed Control File’s

•CF2: Loosing all Multiplexed Control Files (without a backup)

•CF3: Restoring Control File From Autobackup

•CF4: Restore Control File From Recovery Catalog

•CF5: Restore Control File When FRA is Configured

CF1: Loosing one of the Multiplexed Control File’s :

•Problem:

–Database is up

–One of the multiplexed control file is lost

•Solution(s):

1) Copy a good control file to the location of the missing control file

2) Remove references to the missing control file from CONTROL_FILES initialization parameter

Simulating the problem:

•Place one of the Control Files on a Pen Drive

•Remove the pen drive

Errors in file c:\db10g\dump\db10g_ckpt_5836.trc:

  ORA-00206: error in writing (block 3, # blocks 1) of control file

  ORA-00202: control file: 'E:\DB10G\DATA\CONTROL03.CTL'

  ORA-27072: File I/O error

  OSD-04008: WriteFile() failure, unable to write to file

  O/S-Error: (OS 1006) The volume for a file has been externally altered so that the opened file is no longer valid.

CF2: Loosing all Multiplexed Control Files (without a backup) :

•Problem:

–All Control Files are lost

–No backup exists

•Solution:

–Startup database instance in NOMOUNT mode

–Create a new Control File

–Open the database

•Creating a new Control File

–Startup database instance in NOMOUNT mode

–Use NORESETLOGS option as online redo log files are still good

•Open Database

CF3: Restoring Control File From Autobackup:

•Problem:

–All Control Files are lost

–Autobackup is configured

•Solution:

–Start database instance in NOMOUNT mode

–Set DBID in RMAN

–Restore control file from autobackup

–MOUNT the database

–Recover database

–Open the database with RESETLOGS option

•Start database instance in NOMOUNT mode

•Set DBID in RMAN

•Restore Control File

•MOUNT database

•Recover database

•Open database with RESETLOGS option

CF4: Restore Control File From Recovery Catalog :

•Scenario:

–All Control Files are lost

–Recover Catalog is configured

•Solution(s):

–Start database instance in NOMOUNT mode

–Restore control file

–MOUNT the database

–Recover database

–Open the database with RESETLOGS option

•Start database instance in NOMOUNT mode

•Restore Control File

–Setting DBID is not required as recover catalog is configured

CF5: Restore Control File When FRA is Configured

•Problem:

–All Control Files are lost

–Flash Recovery Area (FRA) is configured

–Autobackup feature is disabled

•Solution(s):

–Start database instance in NOMOUNT mode

–Restore control file

–MOUNT the database

–Recover database

–Open the database with RESETLOGS option

•Start database instance in NOMOUNT mode

•Restore Control File

•MOUNT database

•Recover database

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cont.  👇👨👇   

Loss of Redo File :