RAC Crashed due to Corrupted Blocks

Question

Hi,
I've got a RAC system which was crashed due to couple of corrupted blocks. This is 10g r2 standard edition 3 node system with ASM disk.
Is there any way where I can get this system up and running avoiding these corrupted blocks.
Thanks,
Kam.

Answer 1

Step 1: Identify the currupted blocks
Option1:
Following queries will help you identify which block is currupted.
##Read from v$backup_corruption
SELECT distinct 'Data Block# '|| block# || ' of Data File '|| name || ' is corrupted.'
FROM v$backup_corruption a, v$datafile b
WHERE a.file# = b.file#;
##Read from v$copy_corruption
SELECT distinct 'Data Block# '|| block# || ' of Data File '|| name || ' is corrupted.'
FROM v$copy_corruption a, v$datafile b
WHERE a.file# = b.file#;
Option2:
Use DBVERIFY utility to identify currupted blocks.
Ex:
$ dbv file=system_ts_01.dbf start=9 end=25 blocksize=16384 logfile=dbvsys_ts.log feedback=2
Step2: Repair currupted block
Once currupted blocks are identified, use RMAN (assuming you still have the backups without currupted blocks), to recover those blocks.
Recovering Data blocks Using Selected Backups:
# restore from backupset
BLOCKRECOVER DATAFILE 9 BLOCK 13 DATAFILE 2 BLOCK 19 FROM BACKUPSET;
# restore from datafile image copy
BLOCKRECOVER DATAFILE 9 BLOCK 13 DATAFILE 2 BLOCK 19 FROM DATAFILECOPY;
# restore from backupset with tag "mondayAM"
BLOCKRECOVER DATAFILE 9 BLOCK 13 DATAFILE 2 BLOCK 199 FROM TAG = mondayAM;
# restore using backups made before one week ago
BLOCKRECOVER DATAFILE 9 BLOCK 13 DATAFILE 2 BLOCK 19 RESTORE
UNTIL 'SYSDATE-7';
# restore using backups made before SCN 100
BLOCKRECOVER DATAFILE 9 BLOCK 13 DATAFILE 2 BLOCK 19 RESTORE UNTIL SCN 100;
# restore using backups made before log sequence 7024
BLOCKRECOVER DATAFILE 9 BLOCK 13 DATAFILE 2 BLOCK 19 RESTORE
UNTIL SEQUENCE 7024;
For example,
$rman target =rman/rman@rmanprod
RMAN> run {
2> allocate channel ch1 type disk;
3> blockrecover datafile 9 block 13 datafile 2 block 19;
4> }
If the currupted block's segment is an index, rebuilding index will take take care of the currupted block.
You might want to read this nice article written by Vijaya R. Dumpa
http://www.revealnet.com/newsletter-v4/0103_C.htm
--Moid M