SQL> conn / as sysdba
Connected to an idle instance.
SQL> startup nomount
ORACLE instance started.
Total System Global Area 372449280 bytes
Fixed Size 1364732 bytes
Variable Size 331353348 bytes
Database Buffers 33554432 bytes
Redo Buffers 6176768 bytes
SQL> alter database mount standby database;
Database altered.
注意：如果需要进行设备维修或者停机操作，是可以不启动Primary的。