RE: Corrupt unused blocks in sysaux

From: Walker, Jed S <>
Date: Fri, 17 Feb 2012 06:28:06 +0000
Message-ID: <>

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: [] On Behalf Of Walker, Jed S Sent: Tuesday, February 14, 2012 7:47 AM To: Niall Litchfield
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 [] Sent: Tuesday, February 14, 2012 12:53 AM To: Walker, Jed S
Subject: Re: Corrupt unused blocks in sysaux


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 <<>> 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
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Niall Litchfield
Oracle DBA


-- Received on Fri Feb 17 2012 - 00:28:06 CST

Original text of this message