Oracle FAQ Your Portal to the Oracle Knowledge Grid

Home -> Community -> Mailing Lists -> Oracle-L -> Re: RMAN fails because of corrupt block in seemingly free space in SYSTEM

Re: RMAN fails because of corrupt block in seemingly free space in SYSTEM

From: Riyaj Shamsudeen <>
Date: Tue, 02 Jan 2007 15:49:55 -0600
Message-ID: <>

 ('binary' encoding is not supported, stored as-is)


    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 ?

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.

Riyaj Shamsudeen wrote:
> Thanks, Dennis, it was very informative... :)
> Well, in fact Ive put a similar message on Metalink forum, too. As
> for support call, there are some technical difficulties Id rather
> avoid - I said already that they licence is "application use only", so
> all the support goes through us, Id have to cover a few hundreds km
> just to place a SR and then go through all that procedure... sure you
> know, what i mean.
> In fact I advised the local staff to make a manual online database
> copy (instead of RMAN's). The instance does startup all OK, so it
> seems safe enough (though I'm not entirely sure, it's why I'm here).
> Actually they have experienced this problem quite a some time before
> calling on us and have restarted the instance several times already.
> Instance is supposed to work in 24x7 with all what's involved (just
> customer access to the system is limited), so export just won't do.
> I usually can manage - more or less - block corruption and wouldn't
> care much if, in the first place, it wasn't the SYSTEM tablespace. On
> the other hand, I just do not understand why RMAN ever cares about
> this block and why it's fractal, it's in the free space list after
> all. Usually corrupted blocks belong to some certain object, most
> often an index segment, but it's first time on my experience that
> causes a problem being in free space. I seldom use raw devices myself,
> though, that's true, and so there could be some difference.
> I've found few notes in the Metalink with similar symptoms, but, on
> closer look, none of them match the case, neither any of them gives a
> clue. I.e., the mechanics are explainied alright, altogether not in
> the case of a block in a segment in the free segments list.
> Best regards and happy New Year!
> Uldis
> Uldis Pavuls
> DBA, TietoEnator
> 41 Lacplesa Str., Riga, Latvia, LV 1011
> phone +371 7 286 660, fax +371 7 771 313
> <>
> -----Original Message-----
> *From:* Dennis Williams []
> *Sent:* otrdiena, 2007. gada 2. janvr 16:36
> *To:* Pavuls Uldis
> *Cc:*
> *Subject:* Re: RMAN fails because of corrupt block in seemingly
> free space in SYSTEM
> Uldis,
> Hmmm. . . time to place that call to Oracle Support? I think I'd
> try to export my data . . . quickly.
> Dennis Williams

The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. If the reader of this message is not the intended recipient, you are hereby notified that your access is unauthorized, and any review, dissemination, distribution or copying of this message including any attachments is strictly prohibited. If you are not the intended recipient, please contact the sender and delete the material from any computer.

Received on Tue Jan 02 2007 - 15:49:55 CST

Original text of this message