Re: logical corruption

  • From: Mayen.Shah@xxxxxxxxxx
  • To: "Bradd Piontek" <piontekdd@xxxxxxxxx>
  • Date: Fri, 23 May 2008 13:36:33 -0400

I forgot to mention one thing.

There is no error/message in alert.log

I do not want to set maxcorrupt. I would like to leave it as default 0. 
My question was how to check current setting maxcorrupt? Any way that is 
not my concern at this time.

Thanks
Mayen






"Bradd Piontek" <piontekdd@xxxxxxxxx> 
May 23 2008 01:31 PM

To
Mayen Shah/ITS/Lazard@Lazard NYC
cc
oracle-l@xxxxxxxxxxxxx, oracle-l-bounce@xxxxxxxxxxxxx
Subject
Re: logical corruption


Touching on the RMAN piece. Check out the Reference guide and look at the
'SET MAXCORRUPT" setting.

<snip>
Tests data and index blocks that pass physical corruption checks for 
logical
corruption, for example, corruption of a row piece or index entry. If RMAN
finds logical corruption, then it logs the block in the alert.log and 
server
session trace file.
Provided the sum of physical and logical corruptions detected for a file
remain below its MAXCORRUPT setting, the RMAN command completes and
Oracle populates V$DATABASE_BLOCK_CORRUPTION with corrupt block
ranges. If MAXCORRUPT is exceeded, then the command terminates without
populating the views.
Note: For COPY and BACKUP, the MAXCORRUPT setting represents the total
number of physical and logical corruptions permitted on a file.

On Fri, May 23, 2008 at 12:24 PM, <Mayen.Shah@xxxxxxxxxx> wrote:

Hi List, 

env: Oracle 9.2.0.8 Solaris 9 

v$database_block_corruption reported logical corruption for three 
datafiles. 
I ran "backup check logical validate database"   which completed without 
any error. 
dbv  also reported corruption for all three datafiles. 
I did not set maxcorrupt in RMAN so I assume it is set to default 0 (Is 
there any way to check this setting?) 
Last night RMAN full backup completed without any error. 
When I checked, corrupted blocks does not belong to any segment in two 
tablespaces to which these three files belong. (I used dbs_extents to map 
corrupted block to segment) 

This is production database so I am concerned. 

1. Why "rman backup check logical validate database" does not report any 
error? 
2. What are my options? I assume these blocks are marked as soft corrupt. 
Is there any way to repair/reclaim them? 
3. Am I correct to assume that if I do not do any thing these blocks will 
not be used ever and will not cause any issue in future? 

Your valuable guidance is greatly appreciated. 

Thank you. 
Mayen 



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