Oracle Database Discussions

Hi Friends,

I'm trying to configure RMAN backup on Oracle 9.2.0.6 64bit EE Database. Database is running on No-Archive mode, and RMAN Offline backup is scheduled once a week.My backup works sometimes and most of the time it Fails. I wonder what could be the reason. Bellow is RMAN configuration on the database,The script to run offline backup and the Error Msg. I'm looking for help to fix this.

1) RMAN config

RMAN> connect target

connected to target database: RADPRDMH (DBID=3693458060)

RMAN> show all;

using target database controlfile instead of recovery catalog
RMAN configuration parameters are:
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 1 DAYS;
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO 'SBT_TAPE';
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE 'SBT_TAPE' TO '%F';
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F';
CONFIGURE DEVICE TYPE DISK PARALLELISM 1;
CONFIGURE DEVICE TYPE 'SBT_TAPE' PARALLELISM 1;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE 'SBT_TAPE' TO 1;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1;
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE 'SBT_TAPE' TO 1;
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1;
CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT '/u02/backup/SID_df_%t_%s_%p';
CONFIGURE MAXSETSIZE TO UNLIMITED;
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u01/oracle/dbs/snapcf_SID.f'; # default


2) RMAN Script
run {

SHUTDOWN IMMEDIATE;
STARTUP MOUNT;
allocate channel c1 type 'SBT_TAPE' parms
'ENV=(TDPO_OPTFILE=/usr/tivoli/tsm/client/oracle/bin64/tdpo.opt)';
BACKUP DATABASE;
ALTER DATABASE OPEN;
release channel c1;
}

3) Error Msg

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of backup command on c1 channel at 08/22/2008 23:30:09
ORA-19502: write error on file "6gjon78h_1_1", blockno 134996481
(blocksize=512)
ORA-27030: skgfwrt: sbtwrite2 returned error
ORA-19511: Error received from media manager layer, error text:
ANS1235E (RC-72) An unknown system error has occurred from which TSM
cannot recover.