RE: RMAN fails because of corrupt block in seemingly free space in SYSTEM
- From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxxxxx>
- To: <Uldis.Pavuls@xxxxxxxxxxxxxxx>, <rshamsud@xxxxxxxxxxxx>
- Date: Wed, 3 Jan 2007 12:48:10 -0500
I've seen similar looking corruptions on a few of my databases as well. I
never did get to the bottom of the problem. However, in terms of solving the
problem and moving on, you ought to be able to set MAXCORRUPT greater than then
number of corrupt blocks you have, backup the datafile(s) affected, and then,
restore datafile(s) from backup. Since they were corrupt on backup, Oracle
will format the block at restore time. As long as the block is not part of any
segment, that's ok. Note that if any corrupted block is part of any segment,
the above is a bad idea.
-Mark
--
Mark J. Bobak
Senior Oracle Architect
ProQuest Information & Learning
There is nothing so useless as doing efficiently that which shouldn’t be done
at all. –Peter F. Drucker, 1909-2005
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Uldis.Pavuls@xxxxxxxxxxxxxxx
Sent: Wednesday, January 03, 2007 12:35 PM
To: rshamsud@xxxxxxxxxxxx
Cc: oracledba.williams@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: RE: RMAN fails because of corrupt block in seemingly free space in
SYSTEM
Riyai,
it's quite possible the OS partition has been resized, i do not know, my role
is rather consulting at need. I'm not on-site, it makes things a bit difficult.
However, I did not find any tracs of resizing in the alert-log, at least not
for the system tablespace (they certainly had had some difficulties with undo
resizing, however).
In fact there is account for 10 blocks in row corrupted in similar way, all
fractured and with CORRUPTION_CHANGE#=0, rman just falls back on the first,
although, it seems, have recorded other piece of 9 blocks - next to the first
one - in v_$database_block_corruption.Citation:
select T.NAME "T-space", D.NAME "Filename", C."FILE#" "FileId", C."BLOCK#"
"BlockId", C.BLOCKS,
C."CORRUPTION_CHANGE#" "Corr.SCN", C.CORRUPTION_TYPE
from SYS."V_$DATABASE_BLOCK_CORRUPTION" C, SYS."V_$DATAFILE" D,
SYS."V_$TABLESPACE" T
where C."FILE#" = D."FILE#" and D."TS#" = T."TS#" order by 1, 2, 3, 4 ;
<Output as CSV>:
SYSTEM;/dev/rcmssystem;1;65535;1;0;FRACTURED
SYSTEM;/dev/rcmssystem;1;65536;9;0;FRACTURED
<end of output>
All datafiles are locally managed and on raw devices (under VLM on AIX 5.3, so
they are partitions in fact); there should be my first post (2 January, 2007)
with a bit more info.
Thanks for the idea of use of transportable tablespaces, it didn't occur to me.
I'll certainly consider that. I was rather thinking about shrinking that file
and then re-expanding it, that should clear the corruption on success - how do
you think? It would be faster if succeeded. Altogether on the second thought
CORRUPTION_CHANGE#=0 should mean media corruption, so your approach may be
safer in long run.
Best regards,
Uldis
Uldis Pavuls
DBA, TietoEnator
41 Lacplesa Str., Riga, Latvia, LV 1011
phone +371 7 286 660, fax +371 7 771 313
mailto:Uldis.Pavuls@xxxxxxxxxxxxxxx
http://www.tietoenator.com <http://www.tietoenator.com/>
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Riyaj Shamsudeen
Sent: otrdiena, 2007. gada 2. janvārī 23:50
To: Pavuls Uldis
Cc: oracledba.williams@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: Re: RMAN fails because of corrupt block in seemingly free
space in SYSTEM
Uldis
rman does not backup "never used" blocks, not "free" blocks. It is
quite possible that this block was previously used and rman will back this
block also.
Looking at the following lines, clearly even rdba in the block is
corrupted. Many other fields are corrupted too. Weird thing is that block is
corrupted exactly at 65535 block, which happened to be a binary power of 16.
Was this raw device extended using OS tools in the past ? If yes, from what
size ? What is your db_block_size ?
***
Corrupt block relative dba: 0x0040ffff (file 1, block 65535)
Fractured block found during backing up datafile
Data in bad block -
type: 0 format: 2 rdba: 0x0000ffff
last change scn: 0x0000.00000000 seq: 0x1 flg: 0x05
consistency value in tail: 0x0074117a
check value in block header: 0xfef9, computed block checksum: 0x9
spare1: 0x0, spare2: 0x0, spare3: 0x0
***
Can you dump the block itself and print trace lines ? alter system
dump datafile 1 block min 65535 block max 65535
Also, in your SQL, can you select block_id too ?
select TABLESPACE_NAME,FILE_ID,BLOCKS, BLOCK_ID
from SYS.DBA_FREE_SPACE where FILE_ID=1
and BLOCK_ID <=65535 and (BLOCK_ID+BLOCKS-1)>=65535;
Is system locally managed or dictionary managed, in your database ?
I am not sure why Oracle support would say that it is okay to have
corrupt block, that too in a system tablespace. If I were you, I would be
looking at creating a new database and transporting non-system tablespaces from
current database to new database, urgently.
Thanks
Riyaj Shamsudeen
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