今天在公司做oracle 10g rac 增加节点实验，到最后一步添加实例到database中时，只分配一组redo给新加的实例2,导致实例不能启动成功

   [oracle@p650:/oracle/app/oracle]$sqlplus / as sysdba

SQL*Plus: Release 10.2.0.4.0 - Production on Mon May 24 17:01:06 2010

Copyright (c) 1982, 2007, Oracle.  All Rights Reserved.

Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area 1258291200 bytes
Fixed Size                  2083728 bytes
Variable Size             419431536 bytes
Database Buffers          822083584 bytes
Redo Buffers               14692352 bytes
ORA-01618: redo thread 2 is not enabled - cannot mount

检查节点1正常实例

[oracle@p520:/crs/app/oracle/product/crs_1/opmn/conf]$sqlplus "/as sysdba"

SQL*Plus: Release 10.2.0.4.0 - Production on Mon May 24 17:01:21 2010

Copyright (c) 1982, 2007, Oracle.  All Rights Reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP, Data Mining
and Real Application Testing options

SQL> select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES    MEMBERS ARC STATUS
---------- ---------- ---------- ---------- ---------- --- ----------------
FIRST_CHANGE# FIRST_TIME
------------- ------------
         1          1         51   52428800          1 NO  CURRENT
      1251966 24-MAY-10

         2          1         50   52428800          1 NO  INACTIVE
      1194389 20-MAY-10

         3          2          0   52428800          1 YES UNUSED
            0

发现thread 2 实例只有一组日志

oracle 数据库实例日志组最少两组，

在节点1对新增加的实例扩展日志文件

SQL> alter database add logfile thread 2 '/dev/rredo22_lv' size 50m;

Database altered.

SQL> alter database enable thread 2;

Database altered.

SQL> select member from v$logfile;

MEMBER
--------------------------------------------------------------------------------
/dev/rredo11_lv
/dev/rredo12_lv
/dev/rredo21_lv
/dev/rredo22_lv

添加后节点2实例就能正常mount和open了

[oracle@p650:/oracle/app/oracle/admin/orcl/bdump]$sqlplus / as sysdba

SQL*Plus: Release 10.2.0.4.0 - Production on Mon May 24 17:04:48 2010

Copyright (c) 1982, 2007, Oracle.  All Rights Reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP, Data Mining
and Real Application Testing options

SQL> alter database mount;

Database altered.

SQL> alter database open;

Database altered.

SQL>