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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Questions re redo log files
Hi Bill,
>What are the ramifications of using the dbv utility to look at redo logs?
The dbv is an utility that is used to check the integrity of offline and online datafiles. It cannot be used to validate redo logs
>yet when I run the dbv utility I must specify a blocksize of 512 to look at
>the redo logs.
As indicated above, dbv cannot be used for redologs The blocksize in the dbv utility is the Oracle block size. If the block size is 2K then it need not be specified else needs to be specified with the BLOCKSIZE parameter.
>Why is the block size of the redo log files 512? Do I need to worry about
>the fact that the blocksize is different from the rest of the files? Do I
>have any control over this at database creation time?
The redo logs are in OS blocks and not in Oracle blocks. The general OS block size is 512 bytes and the 8192 that you specified does not apply to redo logs but to datafiles
>When I do analyze the redo logs the utility returns the following for each
>page...
>
>DBVERIFY: Release 8.0.5.1.0 - Production on Fri May 19 11:42:33 2000
>
>(c) Copyright 1998 Oracle Corporation. All rights reserved.
>
>
>DBVERIFY - Verification starting : FILE = log01.dbf
>Page 1 is marked corrupt
>***
>Corrupt block relative dba: 0x00000001 file=0. blocknum=1.
>Bad header found during dbv:
>Data in bad block - type:0. format:0. rdba:0x00000001
>last change scn:0x0000.17b90186 seq:0x47 flg:0x65
>consistancy value in tail 0x00000000
>check value in block header: 0x800, calculated check value: 0x0
>spare1:0x2f, spare2:0x59, spare2:0x0
>
>Why does it return to me that there is an error on each page? This does not
>happen with any of the other files. Is this anything I need to worry about?
The reason is dbv is not able to comprehend the file that you have provided as input to it as it does not understand redo log files.
Hope this helps.
Regards,
Madhavan
IBM Corporation Webserver Division
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