[Oracle工程师手记]从RAC环境备份后向新环境(文件系统)恢复的试验

假定备份源是RAC+ASM环境，执行恢复操作的对象服务器是文件系统环境。假定备份源端具有一个称为 /home/grid/mnt的挂载点作为NFS客户端，在还原/恢复目标端，作为 NFS服务器的对应目录是 /home/oracle/formnt。

 我的备份脚本如下：

  Level 0 增量备份：

    run{

    backup incremental level 0 format '+DATA' database;
    sql 'alter system archive log current';
    backup  as backupset format '+DATA' archivelog from time 'sysdate-1';
    backup format '+DATA' current controlfile;

    }

Level 1  增量备份：

  run{

    backup incremental level 1 format '+DATA' database;
    sql 'alter system archive log current';
    backup as backupset format '+DATA' archivelog from time 'sysdate-1';
    backup format '+DATA' current controlfile;
    }

 仅使用0级和1级备份可能无法还原到指定的时间点。因此，上面的脚本中，切换 archive log 并对其进行备份。在执行备份之前，记录一下数据文件和 Online REDO 文件路径。

   SQL> select name from v$datafile;

    NAME
    --------------------------------------------------------------------------------
    +DATA/ORA12102/DATAFILE/system.261.943312827
    +DATA/ORA12102/DATAFILE/sysaux.273.838525691
    +DATA/ORA12102/DATAFILE/undotbs1.276.998325422
    +DATA/ORA12102/DATAFILE/users.262.987321245      

    SQL> select member from gv$logfile;

    MEMBER
    --------------------------------------------------------------------------------
    +DATA/ORA12102/ONLINELOG/group_3.264.954612469
    +DATA/ORA12102/ONLINELOG/group_3.263.954612505
    +DATA/ORA12102/ONLINELOG/group_2.266.954612377
    +DATA/ORA12102/ONLINELOG/group_2.265.954612423
    +DATA/ORA12102/ONLINELOG/group_1.268.954612297
    +DATA/ORA12102/ONLINELOG/group_1.267.954612333

    SQL>

Source 端的备份经过：

    Level 0 增量备份

    RMAN> run{
      backup incremental level 0 format '+DATA' database;
      sql 'alter system archive log current';
      backup  as backupset format '+DATA' archivelog from time 'sysdate-1';
      backup format '+DATA' current controlfile;
    }

模拟数据库的运行：变更一些数据

    SQL> create table tab001 as select * from dba_objects;
    SQL> alter system archive log current;

Level 1 增量备份

    RMAN> run{
     backup incremental level 1 format '+DATA' database;
     sql 'alter system archive log current';
     backup as backupset format '+DATA' archivelog from time 'sysdate-1';
     backup format '+DATA' current controlfile;
    }

检查备份的结果：

    $ export NLS_DATE_FORMAT='YYYYMMDD_HH24:MI:SS'
    $ rman target /

    RMAN> list backup;

    BS Key  Type LV Size   Device Type Elapsed Time Completion Time
    ------- ---- -- ---------- ----------- ------------ -----------------
    5   Incr 0  1.20G  DISK00:04:50 20210407_12:07:23
     BP KEY: 5   STATUS: AVAILABLE  Compressed : NO  TAG: TAG20210407T120233
     PIECE NAME: +DATA/ORA12102/BACKUPSET/2017_09_14/sssdr0_tag20210407t120233_0.260.954676953
    …..
    File LV Type Ckp SCNCkp Time Name
    ---- -- ---- ---------- ----------------- ----
    10  Incr 184119020210407_12:02:33 +DATA/ORA12102/DATAFILE/system.261.943312827
    30  Incr 184119020210407_12:02:33 +DATA/ORA12102/DATAFILE/sysaux.273.838525691
    40  Incr 184119020210407_12:02:33 +DATA/ORA12102/DATAFILE/undotbs1.276.998325422
    60  Incr 184119020210407_12:02:33 +DATA/ORA12102/DATAFILE/users.262.987321245      
    ……

    BS Key  Type LV Size   Device Type Elapsed Time Completion Time
    ------- ---- -- ---------- ----------- ------------ ---------------
    6  Full10.19M DISK00:00:01 20210407_12:07:23
    BP Key: 34   Status: AVAILABLE  Compressed: NO  Tag: TAG: TAG20210407T120233
    Piece Name: /refresh/home/app/12.1.0.2/oracle/product/12.2.0.1/dbhome3/dbs/ncsnn1_tag20210407t125241_0.280.954680049
      SPFILE Included: Modification time: 20210407_12:07:23
      SPFILE db_unique_name: ORA12102
      Control File Included: Ckp SCN: 1950495  Ckp time: 20210407_12:07:23
    <<<<  此处 "SPFILE Include" 是随着 level 0 增分备份执行自动生成的包含 controlfile 和 spfile 信息的备份

    BS Key  Type LV Size   Device Type Elapsed Time Completion Time
    ------- ---------- ----------- ------------ -----------------
    11  31.47M DISK00:00:13 20210407_12:54:35
     BP KEY:11   STATUS: AVAILABLE  Compressed: NO  TAG: TAG20210407T125422
     PIECE NAME: +DATA/ORA12102/BACKUPSET/2017_09_14/annnf0_tag20210407t125422_0.283.954680063

    BS Key  Type LV Size   Device Type Elapsed Time Completion Time
    Thrd Seq Low SCNLow TimeNext SCN   Next Time
    ---- ------- ---------- ----------------- ---------- ---------
    114  183759620210407_11:22:53 184050920210407_11:48:07
    115  184050920210407_11:48:07 184133520210407_12:07:41
    116  184133520210407_12:07:41 184134320210407_12:07:43
    117  184134320210407_12:07:43 184266320210407_12:51:19
    118  184266320210407_12:51:19 184276220210407_12:54:19
    119  184276220210407_12:54:19 184277020210407_12:54:20    <===请记住最新 archive log 的 Next SCN，因为我们将在还原时使用这个值。

    BS Key  Type LV Size   Device Type Elapsed Time Completion Time
    ------- ---- -- ---------- ----------- ------------ -----------------
    12  Full9.61M  DISK00:00:07 20210407_12:54:44
     BP KEY: 12   STATUS: AVAILABLE  COMPRESSION: NO  TAG: TAG20210407T125437
     PIECE NAME : +DATA/ORA12102/BACKUPSET/2017_09_14/ncnnf0_tag20210407t125437_0.284.954680081
    Controlfile included : Ckp SCN: 1842784  Ckp time: 20210407_12:54:37

    RMAN>

 
 使用asmcmd通过NFS将source 端ASM上的备份复制到dest 端。假设此NFS挂载点是 grid 用户主目录下的mnt目录。执行以下操作：

    [root@ol66 ~]# su - grid
    [grid@ol66 ~]$ export ORACLE_SID=+ASM

    ASMCMD>cp +DATA/ORA12102/BACKUPSET/2017_09_14/sssdr0_tag20210407t120233_0.260.954676953  /home/grid/mnt
    ......

将上面 <list backup> 中列出的 备份文件，都拷贝到 dest 端(过程略)。

Dest 端执行恢复操作：

    # su - oracle
    $ . oraenv
    ORACLE_SID = [ora12102] ?   <<<<<<<<<<<<<<<<<  指定 Source 端的 ORACLE_SID
    ORACLE_HOME = [/home/oracle] ? /u01/app/oracle/product/12.1.0/dbhome_1   <<<<<<<<<<<<<<<<<<< 设定 ORACLE_HOME(根据当初安装 Oracle binary 时的设定来指定)
    The Oracle base remains unchanged with value /u01/app/oracle
    $

    利用前面的SPFILE 的备份(ncsnn1_tag20210407t125241_0.280.954680049)，来在 dest 端恢复 SPFILE。

    $ rman target /

    RMAN> startup nomount force;

    Failed to start: ORA-01078: failure in processing system parameters
    LRM-00109: ??????????????????????????????'/u01/app/oracle/product/12.1.0/dbhome_1/dbs/initora12102.ora'?????????????????????????????????
    ...

    RMAN>

 
    不必在意上面的错误，继续执行：

    RMAN> restore spfile from '/home/oracle/formnt/ncsnn1_tag20210407t125241_0.280.954680049';

 
    也作成 PFILE(是为了读取spfile 中的内容，并做出相应更改)

    RMAN> restore spfile to pfile '/home/oracle/initora12102.ora' from '/home/oracle/formnt/ncsnn1_tag20210407t125241_0.280.954680049';

    RMAN> exit

 
    由于source 端是RAC环境，dest 端是 single 环境，因此将 cluster_database设置为false或删除PFILE中的该行。然后检查有关PFILE中每个目录的信息。

    $ cat  initora12102.ora

    ora12102.__data_transfer_cache_size=0
    ora12102.__db_cache_size=1040187392
    ora12102.__java_pool_size=16777216
    ora12102.__large_pool_size=33554432
    ora12102.__oracle_base='/u01/app/oracle'#ORACLE_BASE set from environment
    ora12102.__pga_aggregate_target=503316480
    ora12102.__sga_target=1493172224
    ora12102.__shared_io_pool_size=67108864
    ora12102.__shared_pool_size=318767104
    ora12102.__streams_pool_size=0
    *.audit_file_dest='/u01/app/oracle/admin/ora12102/adump'
    *.audit_trail='db'
    *.compatible='12.1.0.2.0'
    *.control_files='+DATA/ORA12102/CONTROLFILE/current.269.954612287','+DATA/ORA12102/CONTROLFILE/current.272.954612291'
    *.db_block_size=8192
    *.db_create_file_dest='+DATA'
    *.db_domain=''
    *.db_name='ora12102'
    *.db_recovery_file_dest='+DATA'
    *.db_recovery_file_dest_size=4560m
    *.diagnostic_dest='/u01/app/oracle'
    *.dispatchers='(PROTOCOL=TCP) (SERVICE=ora12102XDB)'
    *.open_cursors=300
    *.pga_aggregate_target=470m
    *.processes=300
    *.remote_login_passwordfile='EXCLUSIVE'
    *.sga_target=1410m
    *.undo_tablespace='UNDOTBS1'
    $

    参照上面的内容，在  dest 端，建立好目录。或者修改 pfile 里关于给中目录的信息，建立好对应的目录。

    mkdir -p /u01/app/oracle/admin/ora12102/adump

 
    因为 dest 端是文件系统，所以没有磁盘组，把涉及到磁盘组的内容进行修改，并建立相应目录(如：控制文件所在目录)

    　mkdir -p /u01/app/oracle/fast_recovery_area/CONTROLFILE

    　mkdir -p /u01/app/oracle/oradata/CONTROLFILE

 
    为在文件系统存储数据文件，建立相应的目录。

 mkdir -p /u01/app/oracle/oradata/datafile

 
    为了在文件系统上存储 online redo，也建立好相应的目录。

    　mkdir -p /u01/app/oracle/oradata/logfile

    由于不能使用 ASM磁盘组，所以调整哪些用到磁盘组的路径，变成使用文件系统路径(如 control_files的值)。

    ora12102.__data_transfer_cache_size=0
    ora12102.__db_cache_size=1040187392
    ora12102.__java_pool_size=16777216
    ora12102.__large_pool_size=33554432
    ora12102.__oracle_base='/u01/app/oracle'#ORACLE_BASE set from environment
    ora12102.__pga_aggregate_target=503316480
    ora12102.__sga_target=1493172224
    ora12102.__shared_io_pool_size=67108864
    ora12102.__shared_pool_size=318767104
    ora12102.__streams_pool_size=0
    *.audit_file_dest='/u01/app/oracle/admin/ora12102/adump'
    *.audit_trail='db'
    *.compatible='12.1.0.2.0'
    *.control_files='/u01/app/oracle/fast_recovery_area/CONTROLFILE/control01.ctl','/u01/app/oracle/oradata/CONTROLFILE/control02.ctl'
    *.db_block_size=8192
    *.db_create_file_dest='/u01/app/oracle/oradata'
    *.db_domain=''
    *.db_name='ora12102'
    *.db_recovery_file_dest='/u01/app/oracle/fast_recovery_area'
    *.db_recovery_file_dest_size=4560m
    *.diagnostic_dest='/u01/app/oracle'
    *.dispatchers='(PROTOCOL=TCP) (SERVICE=ora12102XDB)'
    *.open_cursors=300
    *.pga_aggregate_target=470m
    *.processes=300
    *.remote_login_passwordfile='EXCLUSIVE'
    *.sga_target=1410m
    *.undo_tablespace='UNDOTBS1'

 
    现在 PFILE 修改好了，可以再次启动了：

    $ sqlplus / as sysdba

    SQL> shu immediate
    SQL> startup nomount pfile='/home/oracle/initora12102.ora'

    SQL> exit

 
    用 RMAM 恢复 控制文件：

    $ rman target /

    RMAN> restore controlfile from '/home/oracle/formnt/ncnnf0_tag20210407t125437_0.284.954680081';
    RMAN> exit

 
    Source 端，使用的是 ASM 磁盘组，dest 端使用文件系统，所以，设置 db_file_name_convert 和  log_file_name_convert。
    (用到我上面建立好的 目录 /u01/app/oracle/oradata/datafile/ 和 /u01/app/oracle/oradata/logfile/ )

    $ sqlplus / as sysdba
    SQL>create spfile from pfile='/home/oracle/initora12102.ora';

    SQL>shutdown immediate

    SQL>startup mount

    SQL> alter system set db_file_name_convert='+DATA/ORA12102/DATAFILE/','/u01/app/oracle/oradata/datafile/' scope=spfile;
    SQL> alter system set log_file_name_convert='+DATA/ORA12102/ONLINELOG/','/u01/app/oracle/oradata/logfile/' scope=spfile;

    SQL> shutdown immediate

    SQL> startup mount
    SQL> exit

 
    由于在 source 端时，备份建立到了 磁盘组上，控制文件中也是如此记忆的。所以需要在 恢复控制文件之后，重新登记这些 备份的位置。
 

   $ rman target /

    RMAN>

    RMAN> crosscheck backup;
    RMAN> delete expired backup;
    RMAN> catalog start with '/home/oracle/formnt/';  <<<<<<<<  上述拷贝好的备份的位置。

    执行数据库的 restore / recover ：

    RMAN> run{
       set until scn 1842770;   <<<<<<<  这个  SCN 的值，就是我们在 上面 list backup 时看到的最新的 archive log 的 next scn 值    
       restore database;
       recover database;
    }

 
    打开数据库。

    RMAN> alter database open resetlogs;

    RMAN>exit

 
    确认一下新数据库总的 v$datafile 和 v$logfile 中 数据文件和 online redo 内容。

    SQL> select name from v$datafile;
    SQL> select member from v$logfile;
    SQL> exit    

 
    至此，向新环境的恢复操作结束。