在做数据库从单机到RAC恢复的过程中，1节点正常启动，2节点无法mount，提示如下错误：
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SQL> alter database mount;
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alter database mount
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*
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ERROR at line 1:
- ORA-01618: redo thread 2 is not enabled - cannot mount
查看错误说明：
在正常启动的1节点查看发现都是thread 1 的日志，没有thread 2的日志。- [oracle@otdb1 ~]$ oerr ora 1618
- 01618, 00000, "redo thread %s is not enabled - cannot mount"
- // *Cause: The INIT.ORA parameter "thread" requests a thread that is not
- // enabled. A thread must be enabled before it can be mounted.
- // *Action: Shutdown the instance, change the INIT.ORA parameter and startup
- // mounting a different thread. If the database is open in another
- // instance then the thread may be enabled.
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SQL> select * from v$log;
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GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
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---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
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1 1 1 471859200 1 NO CURRENT 1.4430E+13 10-AUG-15
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2 1 0 471859200 1 YES UNUSED 0
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3 1 0 471859200 1 YES UNUSED 0
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4 1 0 471859200 1 YES UNUSED 0
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5 1 0 471859200 1 YES UNUSED 0
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6 1 0 471859200 1 YES UNUSED 0
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7 1 0 471859200 1 YES UNUSED 0
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8 1 0 471859200 1 YES UNUSED 0
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9 1 0 471859200 1 YES UNUSED 0
- 10 1 0 471859200 1 YES UNUSED 0
1）在正常启动的节点1为节点2手工添加日志
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SQL> alter database add logfile thread 2 ('+DATADG') size 450m;
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- Database altered.
- 。。。。。。。。。。。。。
- SQL> alter database enable thread 2;
- Database altered.
- SQL> alter database mount;
- Database altered.
因为单机只有1组日志，恢复的时候在1节点操作，所有日志都应用在1节点，2节点就缺少相关日志。
RAC恢复的时候需要注意。