RAC 环境下修改归档模式

RAC环境下的归档模式切换与单实例稍有不同，主要是共享存储所产生的差异。在这种情况下，我们可以将RAC数据库切换到非集群状态下，仅仅在一个实例上 来实施归档模式切换即可完成RAC数据库的归档模式转换问题。本文主要描述了由非归档模式切换到归档模式，而由非归档切换的归档步骤相同，不再赘述。

1、主要步骤：
 备份spfile，以防止参数修改失败导致数据库无法启动
 修改集群参数cluster_database为false
 启动单实例到mount状态
 将数据库置于归档模式(alter database archivelog/noarchivelog)
 修改集群参数cluster_database为true
 关闭单实例
 启动集群数据库

2、环境
 oracle@bo2dbp:~> cat /etc/issue

 Welcome to SUSE Linux Enterprise Server 10 SP3 (x86_64) - Kernel \r (\l).

 oracle@bo2dbp:~> sqlplus -v

 SQL*Plus: Release 10.2.0.3.0 - Production

 使用asm存储方式存放归档日志

3、修改集群数据库到归档模式
 oracle@bo2dbp:~> export ORACLE_SID=ora10g1
 oracle@bo2dbp:~> sqlplus / as sysdba

 SQL*Plus: Release 10.2.0.3.0 - Production on Mon Dec 24 16:53:18 2012

 Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.

 Connected to:
 Oracle Database 10g Release 10.2.0.3.0 - 64bit Production
 With the Real Application Clusters option

 SQL> archive log list;    -->查看当前数据库的归档模式
 Database log mode              No Archive Mode          -->非归档模式
 Automatic archival             Disabled
 Archive destination            USE_DB_RECOVERY_FILE_DEST
 Oldest online log sequence     59
 Current log sequence           60

 SQL> select instance_name,host_name,status from gv$instance;

 INSTANCE_NAME    HOST_NAME            STATUS
 ---------------- -------------------- ------------
 ora10g1          bo2dbp               OPEN
 ora10g2          bo2dbs               OPEN

 SQL> show parameter cluster      -->查看集群的参数,cluster_database为true表示为集群数据库，否则，非集群数据库

 NAME                                 TYPE        VALUE
 ------------------------------------ ----------- ------------------------------
 cluster_database                     boolean     TRUE
 cluster_database_instances           integer     2
 cluster_interconnects                string

 SQL> create pfile='/u01/oracle/db/dbs/ora10g_robin.ora' from spfile;  -->先备份spfile

 File created.

 SQL> alter system set cluster_database=false scope=spfile sid='*';  -->修改为非集群数据库，该参数为静态参数，需要使用scope=spfile

 System altered.

 oracle@bo2dbp:~> srvctl stop database -d ora10g                        -->关闭数据库
 oracle@bo2dbp:~> srvctl start instance -d ora10g -i ora10g1 -o mount   -->启动单个实例到mount状态
 oracle@bo2dbp:~> sqlplus / as sysdba
 SQL> select instance_name,status from v$instance;

 INSTANCE_NAME    STATUS
 ---------------- ------------
          MOUNTED

 SQL> alter database archivelog;                                       -->改变数据库到归档模式

 Database altered.
alter system set log_archive_dest_1='location=/oracle/app/ora10g1' scope=spfile sid='ora10g1';
alter system set log_archive_dest_1='location=/oracle/app/ora10g2' scope=spfile sid='ora10g2';

 SQL> alter system set cluster_database=true scope=spfile sid='*';    -->在将数据库改为集群模式

 System altered.

 SQL> ho srvctl stop instance -d ora10g -i ora10g1                     -->关闭当前实例

 SQL> ho srvctl start database -d ora10g                               -->启动集群数据库

 SQL> archive log list;
 ORA-03135: connection lost contact
 SQL> conn / as sysdba
 Connected.
 SQL> archive log list;                                                -->查看归档模式
 Database log mode              Archive Mode                           -->已经处于归档模式
 Automatic archival             Enabled                                -->自动归档
 Archive destination            USE_DB_RECOVERY_FILE_DEST              -->归档位置为参数DB_RECOVERY_FILE_DEST的值
 Oldest online log sequence     60                                     -->下面是sequence相关信息
 Next log sequence to archive   61
 Current log sequence           61

 SQL> show parameter db_recovery_file

 NAME                                 TYPE        VALUE
 ------------------------------------ ----------- ------------------------------
 db_recovery_file_dest                string      +REV
 db_recovery_file_dest_size           big integer 2G

4、归档验证
 SQL> select inst_id,name,thread#,sequence#,status from gv$archived_log;  -->当前无任何归档日志

 no rows selected

 SQL> alter system switch logfile;        -->在实例1上进行归档

 System altered.

 SQL> col name format a65
 SQL> select inst_id,name,thread#,sequence#,status from gv$archived_log;   -->查看到sequence为61的日志已经归档

    INST_ID NAME                                                                 THREAD#  SEQUENCE# S
 ---------- ----------------------------------------------------------------- ---------- ---------- -
    1 +REV/ora10g/archivelog/2012_12_24/thread_1_seq_61.459.802892953            1         61

 SQL> select name,thread#,sequence#,status from v$archived_log;  -->下面是从实例级别的视图来查看

 NAME                                                                 THREAD#  SEQUENCE# S
 ----------------------------------------------------------------- ---------- ---------- -
 +REV/ora10g/archivelog/2012_12_24/thread_1_seq_61.459.802892953            1         61 A

 SQL> conn system/oracle@ora10g2    -->连接到实例2
 Connected.
 SQL> show parameter instance_name;

 NAME                                 TYPE        VALUE
 ------------------------------------ ----------- ------------------------------
 instance_name                        string      ora10g2
 SQL> alter system switch logfile;   -->在实例2上进行归档

 System altered.
 SQL> select inst_id,name,thread#,sequence#,status from gv$archived_log;
 -->可以看到sequence为43的日志已经归档
 -->注意这个视图查询时同一个归档日志除了出现在自身实例中外,对另外的实例也是可见的
    INST_ID NAME                                                                 THREAD#  SEQUENCE# S
 ---------- ----------------------------------------------------------------- ---------- ---------- -
    1 +REV/ora10g/archivelog/2012_12_24/thread_1_seq_61.459.802892953            1         61 A
    1 +REV/ora10g/archivelog/2012_12_24/thread_2_seq_43.458.802893283            2         43 A
    2 +REV/ora10g/archivelog/2012_12_24/thread_1_seq_61.459.802892953            1         61 A
    2 +REV/ora10g/archivelog/2012_12_24/thread_2_seq_43.458.802893283            2         43 A

 -->查看日志的状态
 -->注意这个v$log视图将两个实例上的组及状态都显示出来了
 -->在这里用thread#来区分，thread#为1表示实例1上的日志组有1,2,且1处于current状态.thread#2类似.
 SQL> select * from v$log;

  GROUP#    THREAD#  SEQUENCE#      BYTES    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIM
 ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
    1          1         62   52428800          2 NO  CURRENT                4314741 24-DEC-12
    2          1         61   52428800          2 YES ACTIVE                 4312116 24-DEC-12
    3          2         43   52428800          2 YES ACTIVE                 4312300 24-DEC-12
    4          2         44   52428800          2 NO  CURRENT                4315097 24-DEC-12

 -->Author: Robinson
 -->Blog  : http://blog.csdn.net/robinson_0612
 -->归档当前日志,注意该命令在单实例下等同于alter system switch logfile
 -->在rac环境下则不同，那就是所有实例上的current日志都将会被归档
 SQL> alter system archive log current;

 System altered.

 -->下面的查询正好验证了上面的描述
 -->日志62与44正是刚刚上面的命令同时产生的归档日志
 SQL> select inst_id,name,thread#,sequence#,status from gv$archived_log;

    INST_ID NAME                                                                 THREAD#  SEQUENCE# S
 ---------- ----------------------------------------------------------------- ---------- ---------- -
    2 +REV/ora10g/archivelog/2012_12_24/thread_1_seq_61.459.802892953            1         61 A
    2 +REV/ora10g/archivelog/2012_12_24/thread_2_seq_43.458.802893283            2         43 A
    2 +REV/ora10g/archivelog/2012_12_24/thread_2_seq_44.456.802894343            2         44 A
    2 +REV/ora10g/archivelog/2012_12_24/thread_1_seq_62.457.802894341            1         62 A
    1 +REV/ora10g/archivelog/2012_12_24/thread_1_seq_61.459.802892953            1         61 A
    1 +REV/ora10g/archivelog/2012_12_24/thread_2_seq_43.458.802893283            2         43 A
    1 +REV/ora10g/archivelog/2012_12_24/thread_2_seq_44.456.802894343            2         44 A
    1 +REV/ora10g/archivelog/2012_12_24/thread_1_seq_62.457.802894341            1         62 A

 8 rows selected.