Reading corrupted Datafiles offline 2005-09-06 - By -not available-
On Tuesday 06 September 2005 08:42, Parker, Matthew wrote:
> As Jim mentioned there is the DUL (Data Unloader ) tool that Oracle
> consulting can use for you. The normal stated accuracy is 99% depending
on
> your system. It never understood how to follow chained rows. You are
lucky
> to be on 8.1.6 as they never updated the tool to 9i/10g according to the
> developer, ( a project sometime in the future for him).
>
> Give us so more details about what exactly happened and what you have of
> your database, then we may be able to help you.
hi,
here first the short version of what was happend.
First off all, the database belongs to a small customer of our company.
This
customer doesn't take care of the backup what we have learned the hard way.
After a harddisk failure, which was not recoverable, some datafiles get
lost,
other datafile get corrupted and some are totally ok.
Controlfiles are lost
System - Datafile is good
Rollback is totally lost
Redo Logs are good
Temp is good
User_Data was a bunch of 6 Files
File 1 is good
File 2 is corrupted (4 Blocks including Block# 1)
File 3 is corrupted (1 Block)
File 4 is corrupted (2 Blocks including Block# 1)
File 5 is corrupted (48 Blocks including Block# 1)
File 6 is missing
A Problem is, that we are not able to determine the right filename for some
of
the files. The corrupted ones are the result of the recover of the bad hard
-
disk. The original filename was lost, so we are unable to get the right
filename. Unfortunatly dbv is not giving the filename or filenumber as a
result of the offline check.
My intention is now to read or even export the data, which is included in
the
datafiles of the tablespace USER_DATA.
Because of the missing controlfiles, i try to create new ones with the
following SQL:
STARTUP NOMOUNT
CREATE CONTROLFILE REUSE
SET DATABASE SCHU
RESETLOGS
NOARCHIVELOG
MAXLOGFILES 32
MAXLOGMEMBERS 2
MAXDATAFILES 254
MAXINSTANCES 8
MAXLOGHISTORY 907
LOGFILE
GROUP 1 '/pro1/oradata/SCHU/redo01.log' SIZE 10M,
GROUP 2 '/pro1/oradata/SCHU/redo02.log' SIZE 10M,
GROUP 3 '/pro1/oradata/SCHU/redo03.log' SIZE 10M
DATAFILE
'/pro1/oradata/SCHU/system01.dbf',
'/pro1/oradata/SCHU/temp01.dbf',
'/pro1/oradata/SCHU/usr1SCHU.dbf',
'/pro1/oradata/SCHU/usr2SCHU.ora',
'/pro1/oradata/SCHU/usr3SCHU.ora',
'/pro1/oradata/SCHU/usr4SCHU.ora',
'/pro1/oradata/SCHU/usr5SCHU.ora'
CHARACTER SET WE8PC850
;
The init.ora includes the parameter _allow_resetlogs_corruption=true
The above mentioned SQL fails with the following error:
ORA-01503 (See ORA-01503.ora-code.com): CREATE CONTROLFILE gescheitert
ORA-01210 (See ORA-01210.ora-code.com): Datendatei-Header hat physikalischen Fehler
ORA-01110 (See ORA-01110.ora-code.com): Datendatei : '/pro1/oradata/SCHU/usr2SCHU.ora'
sorry for german, here the english translation:
ORA-01503 (See ORA-01503.ora-code.com) CREATE CONTROLFILE failed
ORA-01210 (See ORA-01210.ora-code.com) data file header is media corrupt
ORA-01110 (See ORA-01110.ora-code.com) data file '/pro1/oradata/SCHU/usr2SCHU.ora'
This is my point now. I have to restore the header of the files with a
corrupt
block# 1 i think. But i don't know how.
So i thought about an offline datafile reader like dbv, which is able to
get
the data out of the datafiles.
I will also start to discuss this with the Oracle support as well. But if
someone of you have any ideas, i will of course appreciate this.
Thx in advance.
J?rg
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