RMAN中switch命令怎么用

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SWITCH命令详解

Purpose：目的，即使用switch命令能做什么
Use the SWITCH command to perform either of the following operations:
    Update the file names for a database, tablespace, or data file to the latest image copies available for the specified files
    1.将数据库，表空间或数据文件的文件名更新为指定文件可用的最新映像副本
    Update the file names for data files and temp files for which you have issued a SET NEWNAME command
    2.在run块中发出set netname后在控制文件中更新指定的文件名信息

A SWITCH is equivalent to the SQL statement ALTER DATABASE RENAME FILE: the names of the files in the RMAN repository are updated, but the database does not rename the files at the operating system level.

Prerequisites（先决条件）

RMAN must be connected to a target database. When switching tablespaces, data files, or temp files, the files must be offline. When switching the whole database, the database must not be open.
RMAN必须连接到目标数据库。 切换表空间，数据文件或临时文件时，这些文件必须处于脱机状态。 切换整个数据库时，数据库一定不能打开。

Usage Notes（使用说明）

The SWITCH command deletes the RMAN repository records for the data file copy from the recovery catalog and updates the control file records to status DELETED.
SWITCH命令从恢复目录中删除数据文件副本的RMAN存储库记录，并将控制文件记录更新为DELETED状态。

If RMAN is connected to a recovery catalog, and if the database is using a control file restored from backup, then SWITCH updates the control file with records of any data files known to the recovery catalog but missing from the control file.
如果RMAN连接到恢复目录，并且数据库正在使用从备份还原的控制文件，则SWITCH会更新控制文件，并记录恢复目录已知但控制文件中缺失的任何数据文件。

Execute SWITCH ... TO COPY only at the RMAN prompt. Use SWITCH without TO COPY only within a RUN block.
只在RMAN提示符下执行SWITCH ... TO COPY。 仅在RUN块内使用SWITCH而不要TO COPY。

语法：

SWITCH {DATABASE | DATAFILE datafileSpec [, datafileSpec]... | TABLESPACE ['] tablespace_name ['] [, ['] tablespace_name [']]...} TO COPY

SWITCH {DATAFILE ALL | DATAFILE datafileSpec [TO DATAFILECOPY {' filename ' | TAG ['] tag_name [']}] | TEMPFILE ALL | TEMPFILE tempfileSpec [TO ' filename ']}

Semantics语义

switch

This subclause switches file names for a database, tablespace, or data file to the latest image copies available for the specified files. By executing this command, you avoid restoring data files from backups. Execute SWITCH ... TO COPY only at the RMAN prompt.
这个子句将数据库，表空间或数据文件的文件名切换为可用于指定文件的最新映像副本。 通过执行此命令，可以避免从备份中恢复数据文件。 只在RMAN提示符下执行SWITCH ... TO COPY。



switch File

This subclause updates the names for data files and temp files for which you have issued a SET NEWNAME command. Use this clause only within a RUN block.
本子句更新您为其发出SET NEWNAME命令的数据文件和临时文件的名称。 仅在RUN块中使用此子句。

Examples使用实例
Example 3-55 Switching to Image Copies to Avoid Restoring from Backup（切换到图像副本以避免从备份中恢复）

Assume that a disk fails, rendering all data files in the users tablespace inaccessible. Image copies of all data files in this tablespace exist in the fast recovery area. After starting RMAN and connecting to the database as TARGET, you can run SWITCH to point to the control file to the new data files and then run RECOVER as follows:假设一个磁盘失败，将无法访问用户表空间中的所有数据文件。 快速恢复区域中存在此表空间中所有数据文件的映像副本。 启动RMAN并以TARGET连接到数据库后，可以运行SWITCH指向新文件的控制文件，然后按如下所示运行RECOVER。

sql "ALTER TABLESPACE users OFFLINE IMMEDIATE";
SWITCH TABLESPACE users TO COPY;
RECOVER TABLESPACE users;
SQL "ALTER TABLESPACE users ONLINE";

Example 3-56 Switching Data File File Names After a Restore to a New Location（在还原到新位置后切换数据文件文件名称）

Assume that a disk fails, forcing you to restore a data file to a new disk location. After starting RMAN and connecting to the database as TARGET, you can use the SET NEWNAME command to rename the data file, then RESTORE to restore the missing data file. You run SWITCH to point to the control file to the new data file and then RECOVER. This example allocates both disk and tape channels.假定磁盘发生故障，迫使您将数据文件恢复到新的磁盘位置。 启动RMAN并以TARGET连接到数据库后，可以使用SET NEWNAME命令重命名数据文件，然后使用RESTORE还原缺失的数据文件。 您运行SWITCH指向控制文件到新的数据文件，然后再恢复。 本例分配磁盘和磁带通道。

RUN
{
  ALLOCATE CHANNEL dev1 DEVICE TYPE DISK;
  ALLOCATE CHANNEL dev2 DEVICE TYPE sbt;
  SQL "ALTER TABLESPACE users OFFLINE IMMEDIATE";
  SET NEWNAME FOR DATAFILE '/disk1/oradata/prod/users01.dbf'
                        TO '/disk2/users01.dbf';
  RESTORE TABLESPACE users;
  SWITCH DATAFILE ALL;
  RECOVER TABLESPACE users;
  SQL "ALTER TABLESPACE users ONLINE";
}

实验第一种使用情况，如下：
Update the file names for a database, tablespace, or data file to the latest image copies available for the specified files
  将数据库，表空间或数据文件的文件名更新为指定文件可用的最新映像副本

1.查询表空间文件位置、大小

SQL> select f.file#,
  2         t.name tablespace,
  3         f.name,
  4         trunc(f.bytes / 1048576, 2) size_mb,
  5         to_char(f.creation_time, 'yyyy-mm-dd') creation_time,
  6         status
  7    from v$datafile f, v$tablespace t
  8   where f.ts# = t.ts#
  9   order by f.creation_time;

     FILE# TABLESPACE                     NAME                                                                      SIZE_MB CREATION_T STATUS
---------- ------------------------------ ---------------------------------------------------------------------- ---------- ---------- -------
         1 SYSTEM                         +DATA/dbrac/datafile/system.256.957563979                                     900 2013-08-24 SYSTEM
         2 SYSAUX                         +DATA/dbrac/datafile/sysaux.257.957563979                                     610 2013-08-24 ONLINE
         4 USERS                          +DATA/dbrac/datafile/users.259.957563981                                   171.25 2013-08-24 ONLINE
         3 UNDOTBS1                       +DATA/dbrac/datafile/undotbs1.258.957563981                                   100 2013-08-24 ONLINE
         5 EXAMPLE                        +DATA/dbrac/datafile/example.264.957564205                                 346.25 2017-10-16 ONLINE
         6 UNDOTBS2                       +DATA/dbrac/datafile/undotbs2.265.957564601                                   100 2017-10-16 ONLINE
         7 PERSON_LOB                     +DATA/dbrac/datafile/person_lob.269.957699435                                  10 2017-10-18 ONLINE
         8 TEST                           +DATA/dbrac/datafile/test.270.957699617                                        20 2017-10-18 ONLINE
         9 TEST_IND                       +DATA/dbrac/datafile/test_ind.271.957699627                                    20 2017-10-18 ONLINE
        10 TEST_BLOB                      +DATA/dbrac/datafile/test_blob.273.957699641                                   20 2017-10-18 ONLINE
        11 TEST_IND                       +DATA/dbrac/datafile/test_ind.274.957699781                                   400 2017-10-18 ONLINE
        12 TEST_BLOB                      +DATA/dbrac/datafile/test_blob.275.957699833                                  400 2017-10-18 ONLINE
        13 TEST                           +DATA/dbrac/datafile/test.276.957699883                                       400 2017-10-18 ONLINE

13 rows selected.

--查询asm磁盘组剩余空间：
[grid@dbrac1 ~]$ asmcmd -p
ASMCMD [+] > lsdg
State    Type    Rebal  Sector  Block       AU  Total_MB  Free_MB  Req_mir_free_MB  Usable_file_MB  Offline_disks  Voting_files  Name
MOUNTED  NORMAL  N         512   4096  1048576     30720    22892                0           11446              0             N  DATA/
MOUNTED  NORMAL  N         512   4096  1048576     10240     4610                0            2305              0             N  FRA/
MOUNTED  NORMAL  N         512   4096  1048576      6144     5218             2048            1585              0             Y  OCRVOTE/
ASMCMD [+] >
[grid@dbrac2 ~]$ sqlplus / as sysasm

SQL*Plus: Release 11.2.0.4.0 Production on Thu Oct 19 18:40:22 2017

Copyright (c) 1982, 2013, oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Real Application Clusters and Automatic Storage Management options

SQL> select status from v$instance;

STATUS
------------------------
STARTED
   
SQL> set lines 200
SQL> col name for a15
SQL> select GROUP_NUMBER,NAME,STATE,TYPE,TOTAL_MB,FREE_MB,REQUIRED_MIRROR_FREE_MB,USABLE_FILE_MB,OFFLINE_DISKS,VOTING_FILES from v$asm_diskgroup;

GROUP_NUMBER NAME            STATE                  TYPE           TOTAL_MB    FREE_MB REQUIRED_MIRROR_FREE_MB USABLE_FILE_MB OFFLINE_DISKS VO
------------ --------------- ---------------------- ------------ ---------- ---------- ----------------------- -------------- ------------- --
           1 DATA            MOUNTED                NORMAL            30720      22892                       0          11446             0 N
           2 FRA             MOUNTED                NORMAL            10240       4610                       0           2305             0 N
           3 OCRVOTE         MOUNTED                NORMAL             6144       5218                    2048           1585             0 Y

SQL> select GROUP_NUMBER,DISK_NUMBER,MOUNT_STATUS,HEADER_STATUS,MODE_STATUS,STATE,REDUNDANCY,TOTAL_MB,FREE_MB,NAME,FAILGROUP,PATH from v$asm_disk order by 1,2;

GROUP_NUMBER DISK_NUMBER MOUNT_STATUS   HEADER_STA MODE_STATUS    STATE      REDUNDANCY       TOTAL_MB    FREE_MB NAME            FAILGROUP       PATH
------------ ----------- -------------- ---------- -------------- ---------- -------------- ---------- ---------- --------------- --------------- --------------------
           1           0 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN             15360      11446 DATA_0000       DATA_0000       /dev/asm_data1
           1           1 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN             15360      11446 DATA_0001       DATA_0001       /dev/asm_data2
           2           0 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN              5120       2305 FRA_0000        FRA_0000        /dev/asm_fra1
           2           1 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN              5120       2305 FRA_0001        FRA_0001        /dev/asm_fra2
           3           0 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN              2048       1740 OCRVOTE_0000    OCRVOTE_0000    /dev/asm_ocrvote1
           3           1 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN              2048       1739 OCRVOTE_0001    OCRVOTE_0001    /dev/asm_ocrvote2
           3           2 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN              2048       1739 OCRVOTE_0002    OCRVOTE_0002    /dev/asm_ocrvote3

7 rows selected.

模拟将test磁盘的数据文件由DATA磁盘组迁移到FRA磁盘组：
检查归档：
SQL> arcHive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     65
Next log sequence to archive   66
Current log sequence           66
SQL>
SQL> show parameter recover

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest                string      +FRA
db_recovery_file_dest_size           big integer 4407M
db_unrecoverable_scn_tracking        boolean     TRUE
recovery_parallelism                 integer     0
SQL>
SQL> show parameter log_archive_dest

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest                     string
log_archive_dest_1                   string
log_archive_dest_10                  string
log_archive_dest_11                  string
log_archive_dest_12                  string
省略................

检查test表空间及数据文件大小及位置：
SQL> select f.file#,
  2         t.name tablespace,
  3         f.name,
  4         trunc(f.bytes / 1048576, 2) size_mb,
  5         to_char(f.creation_time, 'yyyy-mm-dd') creation_time,
  6         status
  7    from v$datafile f, v$tablespace t
  8   where f.ts# = t.ts#
  9   and t.name='TEST'
 10   order by f.creation_time;

     FILE# TABLESPACE                     NAME                                                                      SIZE_MB CREATION_T STATUS
---------- ------------------------------ ---------------------------------------------------------------------- ---------- ---------- -------
         8 TEST                           +DATA/dbrac/datafile/test.270.957699617                                        20 2017-10-18 ONLINE
        13 TEST                           +DATA/dbrac/datafile/test.276.957699883                                       400 2017-10-18 ONLINE

SQL> select s.file_name,
  2         s.tablespace_name,
  3         s.bytes / 1024 / 1024 size_m,
  4         s.ONLINE_STATUS,
  5         d.status,
  6         d.contents
  7    from dba_data_files s, dba_tablespaces d
  8   where s.TABLESPACE_NAME = d.TABLESPACE_NAME and s.tablespace_name='TEST';

FILE_NAME                                                    TABLESPACE_NAME                    SIZE_M ONLINE_ STATUS    CONTENTS
------------------------------------------------------------ ------------------------------ ---------- ------- --------- ---------
+DATA/dbrac/datafile/test.270.957699617                      TEST                                   20 ONLINE  ONLINE    PERMANENT
+DATA/dbrac/datafile/test.276.957699883                      TEST                                  400 ONLINE  ONLINE    PERMANENT

SQL>

--使用rman备份表空间test，模式是映像副本copy:
sql "alter tablespace test offline";
backup as copy datafile 8 format '+fra';
backup as copy datafile 13 format '+fra';
switch datafile 8 to copy;
switch datafile 13 to copy;
--recover datafile 8;
--recover datafile 13;
sql "alter tablespace test online";

注意：recover可以省略，因为offline如下
OFFLINE NORMAL Specify NORMAL to flush all blocks in all data files in the tablespace out of the system global area (SGA). You need not perform media recovery on this tablespace before bringing it back online. This is the default.

操作记录省略.........

执行后查询：
SQL> l
  1  select f.file#,
  2         t.name tablespace,
  3         f.name,
  4         trunc(f.bytes / 1048576, 2) size_mb,
  5         to_char(f.creation_time, 'yyyy-mm-dd') creation_time,
  6         status
  7    from v$datafile f, v$tablespace t
  8   where f.ts# = t.ts#
  9   and t.name='TEST'
 10*  order by f.creation_time
SQL> /

     FILE# TABLESPACE                     NAME                                                            SIZE_MB CREATION_T STATUS
---------- ------------------------------ ------------------------------------------------------------ ---------- ---------- -------
         8 TEST                           +FRA/dbrac/datafile/test.264.957814459                               20 2017-10-18 ONLINE
        13 TEST                           +FRA/dbrac/datafile/test.362.957812657                              400 2017-10-18 ONLINE

SQL>

再次执行将test表空间文件由FRA磁盘组迁移到DATA磁盘组上：
sql "alter tablespace test offline";
backup as copy datafile 8 format '+DATA';
backup as copy datafile 13 format '+DATA';
switch datafile 8 to copy;
switch datafile 13 to copy;
sql "alter tablespace test online";

操作如下：
RMAN> sql "alter tablespace test offline";

sql statement: alter tablespace test offline

RMAN> backup as copy datafile 8 format '+DATA';

Starting backup at 2017-10-19 19:49:23
using channel ORA_DISK_1
channel ORA_DISK_1: starting datafile copy
input datafile file number=00008 name=+FRA/dbrac/datafile/test.264.957814459
output file name=+DATA/dbrac/datafile/test.278.957815365 tag=TAG20171019T194923 RECID=8 STAMP=957815367
channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:07
Finished backup at 2017-10-19 19:49:31

RMAN> backup as copy datafile 13 format '+DATA';

Starting backup at 2017-10-19 19:49:37
using channel ORA_DISK_1
channel ORA_DISK_1: starting datafile copy
input datafile file number=00013 name=+FRA/dbrac/datafile/test.362.957812657
output file name=+DATA/dbrac/datafile/test.277.957815379 tag=TAG20171019T194937 RECID=9 STAMP=957815430
channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:55
Finished backup at 2017-10-19 19:50:33

RMAN>  switch datafile 8 to copy;

datafile 8 switched to datafile copy "+DATA/dbrac/datafile/test.278.957815365"

RMAN> switch datafile 13 to copy;

datafile 13 switched to datafile copy "+DATA/dbrac/datafile/test.277.957815379"

RMAN> sql "alter tablespace test online";

sql statement: alter tablespace test online

RMAN>

最后验证：
SQL> l
  1  select s.file_name,
  2         s.tablespace_name,
  3         s.bytes / 1024 / 1024 size_m,
  4         s.ONLINE_STATUS,
  5         d.status,
  6         d.contents
  7    from dba_data_files s, dba_tablespaces d
  8*  where s.TABLESPACE_NAME = d.TABLESPACE_NAME and s.tablespace_name='TEST'
SQL> /

FILE_NAME                                                    TABLESPACE_NAME                    SIZE_M ONLINE_ STATUS    CONTENTS
------------------------------------------------------------ ------------------------------ ---------- ------- --------- ---------
+DATA/dbrac/datafile/test.278.957815365                      TEST                                   20 ONLINE  ONLINE    PERMANENT
+DATA/dbrac/datafile/test.277.957815379                      TEST                                  400 ONLINE  ONLINE    PERMANENT

SQL>
  1  select f.file#,
  2         t.name tablespace,
  3         f.name,
  4         trunc(f.bytes / 1048576, 2) size_mb,
  5         to_char(f.creation_time, 'yyyy-mm-dd') creation_time,
  6         status
  7    from v$datafile f, v$tablespace t
  8   where f.ts# = t.ts#
  9   and t.name='TEST'
 10   order by f.creation_time;

     FILE# TABLESPACE                     NAME                                                            SIZE_MB CREATION_T STATUS
---------- ------------------------------ ------------------------------------------------------------ ---------- ---------- -------
         8 TEST                           +DATA/dbrac/datafile/test.278.957815365                              20 2017-10-18 ONLINE
        13 TEST                           +DATA/dbrac/datafile/test.277.957815379                             400 2017-10-18 ONLINE

SQL> select GROUP_NUMBER,DISK_NUMBER,MOUNT_STATUS,HEADER_STATUS,MODE_STATUS,STATE,REDUNDANCY,TOTAL_MB,FREE_MB,NAME,FAILGROUP,PATH from v$asm_disk order by 1,2;

GROUP_NUMBER DISK_NUMBER MOUNT_STATUS   HEADER_STA MODE_STATUS    STATE      REDUNDANCY       TOTAL_MB    FREE_MB NAME            FAILGROUP       PATH
------------ ----------- -------------- ---------- -------------- ---------- -------------- ---------- ---------- --------------- --------------- --------------------
           1           0 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN             15360      11023 DATA_0000       DATA_0000       /dev/asm_data1
           1           1 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN             15360      11023 DATA_0001       DATA_0001       /dev/asm_data2
           2           0 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN              5120       2967 FRA_0000        FRA_0000        /dev/asm_fra1
           2           1 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN              5120       2967 FRA_0001        FRA_0001        /dev/asm_fra2
           3           0 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN              2048       1740 OCRVOTE_0000    OCRVOTE_0000    /dev/asm_ocrvote1
           3           1 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN              2048       1739 OCRVOTE_0001    OCRVOTE_0001    /dev/asm_ocrvote2
           3           2 CACHED         MEMBER     ONLINE         NORMAL     UNKNOWN              2048       1739 OCRVOTE_0002    OCRVOTE_0002    /dev/asm_ocrvote3

7 rows selected.

SQL> select GROUP_NUMBER,NAME,STATE,TYPE,TOTAL_MB,FREE_MB,REQUIRED_MIRROR_FREE_MB,USABLE_FILE_MB,OFFLINE_DISKS,VOTING_FILES from v$asm_diskgroup;

GROUP_NUMBER NAME            STATE      TYPE           TOTAL_MB    FREE_MB REQUIRED_MIRROR_FREE_MB USABLE_FILE_MB OFFLINE_DISKS VO
------------ --------------- ---------- ------------ ---------- ---------- ----------------------- -------------- ------------- --
           1 DATA            MOUNTED    NORMAL            30720      22046                       0          11023             0 N
           2 FRA             MOUNTED    NORMAL            10240       5934                       0           2967             0 N
           3 OCRVOTE         MOUNTED    NORMAL             6144       5218                    2048           1585             0 Y

[grid@dbrac1 ~]$ asmcmd lsdg
State    Type    Rebal  Sector  Block       AU  Total_MB  Free_MB  Req_mir_free_MB  Usable_file_MB  Offline_disks  Voting_files  Name
MOUNTED  NORMAL  N         512   4096  1048576     30720    22046                0           11023              0             N  DATA/
MOUNTED  NORMAL  N         512   4096  1048576     10240     5934                0            2967              0             N  FRA/
MOUNTED  NORMAL  N         512   4096  1048576      6144     5218             2048            1585              0             Y  OCRVOTE/
[grid@dbrac1 ~]$

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