Oracle Instances Crashes daily

[petso49]

I am faced with a problem on our Server which crashes the instance. This just started happening on 1/26/02. It now
happens once every day during peak/update operations.
Following is the Error message:

*** SESSION ID:(3.1) 2001.10.25.17.03.09.273
error 471 detected in background process
OPIRIP: Uncaught error 447. Error stack:

ORA-00447: fatal error in background process
ORA-00471: DBWR process terminated with error

Dump file T:\ORANT\RDBMS73\trace\orclLGWR.TRC
Wed Jan 30 17:31:43 2002

*** SESSION ID:(3.1) 2002.01.23.17.16.14.898
ORA-00345: redo log write error block 15404 count 2
ORA-00312: online log 2 thread 1: 'T:\ORANT\DATABASE\LOG3ORCL.DBF'
ORA-09205: sfqio: error reading or writing to disk
OSD-04016: Error queuing an asynchronous I/O request.
O/S-Error: (OS 33) The process cannot access the file because another process has locked a portion of the file.
ORA-00346: log member marked as STALE
ORA-00312: online log 2 thread 1: 'T:\ORANT\DATABASE\LOG3ORCL.DBF'

Our server is on Oracle 7.3.4 and Windows 2000 Server. I have looked up both error messages for explanation.
but since there is also an operating system error code (OSD-0416) with the Oracle error, I cannot find the
specifics (or other messages in our Trace files) that explains why this happened?

Is there somewhere or something specific I can look for that causes this problem? How do I fix/correct the problem? Help! Thanks.

[Knarayan]

Check if any backup software is locking this file at certain times which leads to the LGWR process terminating as the file is locked/ not available to write to the file.

You can find out oS error by typing:
net helpmsg from the command prompt for OS errors.

Hope this helps

[petso49]

We are using backup.exe which runs at 3 am. These crashes happen around 3-5 pm. Net helpmsg did not help me. Thanks KN for responding.

[gandolf989]

Are you running any virus checking at 3 PM.