请教NBU备份奇怪问题

cincr_backup 策略调用的脚本文件 cincr_backup.sh 如下：
CUSER=`whoami`


RMAN_LOG_FILE=${0}.out


if [ -f "$RMAN_LOG_FILE" ]
then
        rm -f "$RMAN_LOG_FILE"
fi


echo >> $RMAN_LOG_FILE
chmod 666 $RMAN_LOG_FILE


echo Script $0 >> $RMAN_LOG_FILE
echo ==== started on `date '+%F %T'` ==== >> $RMAN_LOG_FILE
echo >> $RMAN_LOG_FILE


ORACLE_HOME=/oracle/product/database
export ORACLE_HOME


ORACLE_SID=wxxrdb1
export ORACLE_SID


ORACLE_USER=oracle


TARGET_CONNECT_STR=sys/caserver


RMAN=$ORACLE_HOME/bin/rman


echo >> $RMAN_LOG_FILE
echo   "RMAN: $RMAN" >> $RMAN_LOG_FILE
echo   "ORACLE_SID: $ORACLE_SID" >> $RMAN_LOG_FILE
echo   "ORACLE_USER: $ORACLE_USER" >> $RMAN_LOG_FILE
echo   "ORACLE_HOME: $ORACLE_HOME" >> $RMAN_LOG_FILE


echo  >> $RMAN_LOG_FILE
echo   "NB_ORA_FULL: $NB_ORA_FULL" >> $RMAN_LOG_FILE
echo   "NB_ORA_INCR: $NB_ORA_INCR" >> $RMAN_LOG_FILE
echo   "NB_ORA_CINC: $NB_ORA_CINC" >> $RMAN_LOG_FILE
echo   "NB_ORA_SERV: $NB_ORA_SERV" >> $RMAN_LOG_FILE
echo   "NB_ORA_POLICY: $NB_ORA_POLICY" >> $RMAN_LOG_FILE


echo >> $RMAN_LOG_FILE

if [ "$NB_ORA_FULL" = "1" ]
then
        echo "Full backup requested" >> $RMAN_LOG_FILE
        BACKUP_TYPE="INCREMENTAL LEVEL=0"

elif [ "$NB_ORA_INCR" = "1" ]
then
        echo "Differential incremental backup requested" >> $RMAN_LOG_FILE
        BACKUP_TYPE="INCREMENTAL LEVEL=1"

elif [ "$NB_ORA_CINC" = "1" ]
then
        echo "Cumulative incremental backup requested" >> $RMAN_LOG_FILE
        BACKUP_TYPE="INCREMENTAL LEVEL=1 CUMULATIVE"

elif [ "$BACKUP_TYPE" = "" ]
then
        echo "Default - Full backup requested" >> $RMAN_LOG_FILE
        BACKUP_TYPE="INCREMENTAL LEVEL=0"
fi



CMD_STR="
ORACLE_HOME=$ORACLE_HOME
export ORACLE_HOME
ORACLE_SID=$ORACLE_SID
export ORACLE_SID
$RMAN target $TARGET_CONNECT_STR nocatalog msglog $RMAN_LOG_FILE append << EOF
RUN {
ALLOCATE CHANNEL ch00 TYPE 'SBT_TAPE';
ALLOCATE CHANNEL ch01 TYPE 'SBT_TAPE';
BACKUP
    $BACKUP_TYPE
   # SKIP INACCESSIBLE
    TAG hot_db_bk_incr1`date '+%y%m%d%H%M%S'`
    FILESPERSET 5
    # recommended format
    FORMAT 'bk_%s_%p_%t'
    DATABASE include current controlfile plus archivelog;
    sql 'alter system archive log current';
RELEASE CHANNEL ch00;
RELEASE CHANNEL ch01;
}
EOF
"

if [ "$CUSER" = "root" ]
then
    su - $ORACLE_USER -c "$CMD_STR" >> $RMAN_LOG_FILE
    RSTAT=$?
else
    /usr/bin/sh -c "$CMD_STR" >> $RMAN_LOG_FILE
    RSTAT=$?
fi


if [ "$RSTAT" = "0" ]
then
    LOGMSG="ended successfully"
else
    LOGMSG="ended in error"
fi

echo >> $RMAN_LOG_FILE
echo Script $0 >> $RMAN_LOG_FILE
echo ==== $LOGMSG on `date '+%F %T'` ==== >> $RMAN_LOG_FILE
echo >> $RMAN_LOG_FILE

exit $RSTAT