DG备库执行只读open的时候报错

10.2.0.4RAC到单机

--DG备库执行只读open的时候报错
SQL> alter database open read only
  2  ;
alter database open read only
*
ERROR at line 1:
ORA-16004: backup database requires recovery
ORA-01152: file 1 was not restored from a sufficiently old backup
ORA-01110: data file 1: '/u01/app/orcl/datafile/system.dbf '

--那就recover
RMAN> recover datafile 1;

Starting recover at 22-DEC-15
using channel ORA_DISK_1

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 12/22/2015 07:50:20
RMAN-06067: RECOVER DATABASE required with a backup or created control file

--recover数据库
RMAN>  RECOVER DATABASE
2> ;

Starting recover at 22-DEC-15
using channel ORA_DISK_1

starting media recovery

unable to find archive log
archive log thread=2 sequence=12
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 12/22/2015 07:55:19
RMAN-06054: media recovery requesting unknown log: thread 2 seq 12 lowscn 723823

--那就去主端找日志文件：
ASMCMD [+fra/orcl/archivelog/2015_12_21] > ls  
thread_1_seq_1.257.899049055
thread_1_seq_2.258.899049063
thread_1_seq_3.259.899052839
thread_1_seq_4.261.899052841
thread_1_seq_5.263.899056385
thread_1_seq_6.265.899056387
thread_2_seq_1.256.899048997
thread_2_seq_2.260.899052839
thread_2_seq_3.262.899056381
thread_2_seq_4.264.899056387
ASMCMD [+fra/orcl/archivelog/2015_12_21] > cd ..
ASMCMD [+fra/orcl/archivelog] > cd 2015_12_22
ASMCMD [+fra/orcl/archivelog/2015_12_22] > ls
thread_1_seq_10.272.899102315
thread_1_seq_11.276.899102395
thread_1_seq_12.277.899102395
thread_1_seq_13.278.899102397
thread_1_seq_14.279.899102397
thread_1_seq_15.280.899102399
thread_1_seq_7.266.899097735
thread_1_seq_8.269.899100055
thread_1_seq_9.270.899100059
thread_2_seq_10.275.899102393
thread_2_seq_11.281.899102401
thread_2_seq_5.267.899097797
thread_2_seq_6.268.899097799
thread_2_seq_7.271.899102277
thread_2_seq_8.273.899102389
thread_2_seq_9.274.899102391

后来听说，10g不能打开。只读open是11g的特性。。。