演示如下：

启动到nomount状态

SYS@kyeupdbfs> startup nomount;

ORACLE instance started.

Total System Global Area 1720328192 bytes

Fixed Size		    2253944 bytes

Variable Size		  754977672 bytes

Database Buffers	  956301312 bytes

Redo Buffers		    6795264 bytes

设置trace

SYS@kyeupdbfs> oradebug setmypid;

Statement processed.

SYS@kyeupdbfs> oradebug tracefile_name;

/oracle/app/oracle/diag/rdbms/kyeupdbfs/kyeupdbfs/trace/kyeupdbfs_ora_13343.trc

SYS@kyeupdbfs> alter session set events '10046 trace name context forever,level 12';

Session altered.

启动数据库到mount状态并打开

SYS@kyeupdbfs> alter database mount;

Database altered.

SYS@kyeupdbfs> alter database open;

Database altered.

查阅trace

路径：/oracle/app/oracle/diag/rdbms/kyeupdbfs/kyeupdbfs/trace/kyeupdbfs_ora_13343.trc

查阅trace的另外方法 v$diag_info 视图

SYS@kyeupdbfs> select * from v$diag_info where name like '%Trace%';

   INST_ID NAME 		VALUE

---------- -------------------- --------------------------------------------------

	 1 Diag Trace		/oracle/app/oracle/diag/rdbms/kyeupdbfs/kyeupdbfs/

				trace

	 1 Default Trace File	/oracle/app/oracle/diag/rdbms/kyeupdbfs/kyeupdbfs/

				trace/kyeupdbfs_ora_13343.trc