RMAN中switch命令怎么用

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SWITCH 命令詳解

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. 將數據庫，表空間或數據文件的文件名更新為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 塊中發出 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（先決條件）

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 必須連接到目標數據庫。切換表空間，數據文件或臨時文件時，這些文件必須處于脫機狀態。切換整個數據庫時，數據庫一定不能打開。

Usage Notes（使用說明）

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 命令從恢復目錄中刪除數據文件副本的 RMAN 存儲庫記錄，并將控制文件記錄更新為 DELETED 狀態。

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 連接到恢復目錄，并且數據庫正在使用從備份還原的控制文件，則 SWITCH 會更新控制文件，并記錄恢復目錄已知但控制文件中缺失的任何數據文件。

Execute SWITCH … TO COPY only at the RMAN prompt. Use SWITCH without TO COPY only within a RUN block.
只在 RMAN 提示符下執行 SWITCH … TO COPY。僅在 RUN 塊內使用 SWITCH 而不要 TO COPY。

語法：

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 語義

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.
這個子句將數據庫，表空間或數據文件的文件名切換為可用于指定文件的最新映像副本。通過執行此命令，可以避免從備份中恢復數據文件。只在 RMAN 提示符下執行 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.
本子句更新您為其發出 SET NEWNAME 命令的數據文件和臨時文件的名稱。僅在 RUN 塊中使用此子句。

Examples 使用實例
Example 3-55 Switching to Image Copies to Avoid Restoring from Backup（切換到圖像副本以避免從備份中恢復）

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: 假設一個磁盤失敗，將無法訪問用戶表空間中的所有數據文件。快速恢復區域中存在此表空間中所有數據文件的映像副本。啟動 RMAN 并以 TARGET 連接到數據庫后，可以運行 SWITCH 指向新文件的控制文件，然后按如下所示運行 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（在還原到新位置后切換數據文件文件名稱）

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. 假定磁盤發生故障，迫使您將數據文件恢復到新的磁盤位置。啟動 RMAN 并以 TARGET 連接到數據庫后，可以使用 SET NEWNAME 命令重命名數據文件，然后使用 RESTORE 還原缺失的數據文件。您運行 SWITCH 指向控制文件到新的數據文件，然后再恢復。本例分配磁盤和磁帶通道。

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
}

實驗第一種使用情況，如下：
Update the file names for a database, tablespace, or data file to the latest image copies available for the specified files
將數據庫，表空間或數據文件的文件名更新為指定文件可用的最新映像副本

1. 查詢表空間文件位置、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.

– 查詢 asm 磁盤組剩余空間：
[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

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.

模擬將 test 磁盤的數據文件由 DATA 磁盤組遷移到 FRA 磁盤組：
檢查歸檔：
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 …………….

檢查 test 表空間及數據文件大小及位置：
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 備份表空間 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，因為 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.

操作記錄省略 ………

執行后查詢：
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

再次執行將 test 表空間文件由 FRA 磁盤組遷移到 DATA 磁盤組上：
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

最后驗證：
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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