RE: Corrupt unused blocks in sysaux
Date: Fri, 17 Feb 2012 06:28:06 +0000
Message-ID: <BAA6E28B6241F046AED1E62D8697516C562D3FE3_at_COPDCEXMB08.cable.comcast.com>
I had to use "set maxcorrupt" to get the backup to work, but since they are unused blocks it should not matter. I am probably going to do the work next week. I'll update afterwards - hopefully with good news.
-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Walker, Jed S
Sent: Tuesday, February 14, 2012 7:47 AM
To: Niall Litchfield
Cc: oracle-l_at_freelists.org
Subject: RE: Corrupt unused blocks in sysaux
Thanks for all the tips. My example below was using note 336133.1. That is why I was asking here, the note isn't working. I had considered exporting everything in SYSAUX and recreating but given what SYSAUX is I found that worrisome. Niall: That is a great idea. I had used "backup validate" to see if it would report the issue and it didn't. Obviously because it didn't look at the unused blocks. So, yes, theoretically if I could back up the SYSAUX table, and then restore/recover it from the backup I can probably eliminate the problem.
From: Niall Litchfield [mailto:niall.litchfield_at_gmail.com]
Sent: Tuesday, February 14, 2012 12:53 AM
To: Walker, Jed S
Cc: oracle-l_at_freelists.org
Subject: Re: Corrupt unused blocks in sysaux
Jed,
I'm afraid I think you'll end up recreating the database (either via export/import or by reversing streams) See Note 950128.1. Most but not all of SYSAUX is moveable. Couple of wilder ideas.
- Try backing up the datafile with RMAN (it shouldn't write the empty blocks but I'd expect it to fail reading them)
- Try shutting down the db and physically moving the file to a different device (should tell you if the file is physically corrupt), you could then do a rename. The 'correct' thing to do is covered in the note though :(
On Mon, Feb 13, 2012 at 11:18 PM, Walker, Jed S <Jed_Walker_at_cable.comcast.com<mailto:Jed_Walker_at_cable.comcast.com>> wrote: Someone just brought me to a system that recently had an outage. A disk had gone bad and been replaced (supposedly RAID1). The database was restarted and appears to be working normally; however, there are some corrupt blocks. I first saw this in the alert log and then verified with dbv. So, now I have corrupt blocks in SYSAUX that are not used by an object. Unfortunately there are no RMAN backups as it appears they use streams to replicate to another database.
I tried creating an object in the sysaux tables so I could allocate extents to encompass the blocks and then insert rows hoping to reformat them; however, when I tried to allocate over the blocks I get a corruption message. I'm thinking these are corrupt on disk.
I re-found dbms_repair but the options for marking blocks corrupt seem to be if the blocks are in an object, not free.
Any ideas on what else I can do? I'd really like to just mark off the blocks and be done with it. (This project is hopefully obsolete later this year).
DBVERIFY - Verification starting : FILE = /var/local/u01/app/oracle/oradata/orcl/sysaux.dbf Page 8450 is influx - most likely media corrupt Page 8451 is marked corrupt Page 8452 is marked corrupt Page 8453 is marked corrupt Page 8454 is marked corrupt
select segment_name, segment_type, owner from dba_extents where file_id = 3 and (
8451 between block_id and block_id + blocks -1 or 8452 between block_id and block_id + blocks -1 or 8453 between block_id and block_id + blocks -1 or 8454 between block_id and block_id + blocks -1)
/
no rows selected
connect jed/*
SQL> create table remcorr (n number, c varchar2(4000)) nologging SQL> tablespace sysaux;
Table created.
SQL> alter table remcorr allocate extent;
Table altered.
SQL> alter table remcorr allocate extent (size 200m);
alter table remcorr allocate extent (size 200m)
*
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 3, block # 8451)
ORA-01110: data file 3: '/var/local/u01/app/oracle/oradata/orcl/sysaux.dbf'
Jed S. Walker, OCP
Principal Engineer, Databases
National Video Advanced Services
Office: 303.267.6759<tel:303.267.6759>
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Niall Litchfield
Oracle DBA
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Received on Fri Feb 17 2012 - 00:28:06 CST