写了个小脚本，用在DG备端开机自启动:

#!/bin/sh
#db auto be mount status when os restart
#20151224

su - oracle -c "sqlplus / as sysdba"<<EOF

startup nomount;
alter database mount standby database;
alter database recover managed standby database using current logfile disconnect from session;
EOF

su - oracle -c "lsnrctl start"

写到一个sh文件中，给x权限，然后把脚本放到rc.local里，就可以了！！