用 RMAN 備份異機恢復 遷移資料

先假設一種情況，假設有一個資料庫，資料量是2T。 如果要對這個資料庫進行遷移，在不考慮磁碟空間的前提下，要求在最短的時間內完成切換操作。

在不考慮磁碟空間前提下，備份時間，網路傳輸時間，恢復時間。 這個時間對於7*24*365的系統來說，肯定是沒辦法承受的。

如果在考慮下備份空間+遷移後的空間。 這個對磁碟的開銷也是非常大。

在我的前一篇Blog裡，提到了RMAN的異機恢復，這種方法可以縮短我們DB的遷移時間。 但是空間問題還沒有解決。在這一篇，我們主要從遷移時間的角度來考慮這個問題。

RMAN 備份異機恢復 並建立新DBID

http://blog.csdn.net/tianlesoftware/archive/2011/03/11/6240983.aspx

在異機恢復中，我們最後對db 是用open resetlogs的方式開啟的。

我們先看open resetlogs的影響:

（1）如果current online redo可以訪問，那麼對其進行歸檔操作。 然後清空所有online redo 的內容，並將日誌的序列設定為1.

（2）如果online redo 不存在，就建立online redo。 這個位置是在控制檔案裡記錄的。 我們在做RMAN 異機恢復的時候，驗證過這點。

（3）開始一個新的incarnation，初始化redo thread和 online redo 在控制檔案中的記錄。

比如：將redo thread 的狀態設定為closed，在redo thread的記錄中設定當前的log sequence 為1. 設定每個redo thread 的checkpoint 到log sequence 1。

從每個thread 選擇一個redo log，並設定其sequence 為1.

（4）在控制檔案中更新當前所有的datafile 和online redo logs，及以後的歸檔檔案用新的resetlog SCN 和 time stamp。

注意： open resetlogs 不會充值SCN.

一般用open resetlogs 開啟資料庫之後，建議立即對資料庫進行一次備份。

下面是一個遷移的測試：

1. 在Target 庫rman 備份資料庫，並將備份copy到Auxiliary庫的相同位置

RMAN 的恢復對備份位置有講究，對於nocatalog模式下，這些備份的位置是寫在控制檔案裡的。所以目錄結構要相同。

關於RMAN 的shell 備份指令碼，參考：

Nocatalog 下的RMAN 增量備份 shell指令碼

http://blog.csdn.net/tianlesoftware/archive/2011/01/26/6164931.aspx

[oracle@qs-dmm-rh1 backup]$ scp * 192.168.2.43:/u01/backup

oracle@192.168.2.43's password:

arch_23m709vi_1_1_20110312 100% 6431KB 6.3MB/s 00:00

ctl_file_24m709vn_1_1_20110312 100% 9568KB 9.3MB/s 00:01

dave_lev0_1rm709u9_1_1_20110312 100% 610MB 12.0MB/s 00:51

dave_lev0_1sm709u9_1_1_20110312 100% 399MB 11.7MB/s 00:34

dave_lev0_1tm709u9_1_1_20110312 100% 4728KB 4.6MB/s 00:00

dave_lev0_1vm709uk_1_1_20110312 100% 1344KB 1.3MB/s 00:01

dave_spfile_25m709vp_1_1_20110312 100% 96KB 96.0KB/s 00:00

2. 在Auxiliary庫建立相關的目錄，口令檔案，和初始化檔案。

初始化檔案可以直接從Target copy過來。如果目錄結構相同的話，都不用修改引數。

3. 用初始化檔案將資料庫啟動到noumout狀態。

SQL> startup nomount pfile=?/dbs/initdave.ora

ORACLE instance started.

Total System Global Area 196681728 bytes

Fixed Size 1335444 bytes

Variable Size 83890028 bytes

Database Buffers 109051904 bytes

Redo Buffers 2404352 bytes

4. 恢復控制檔案

RMAN> restore controlfile from '/u01/backup/ctl_file_2qm72jcf_1_1_20110312';

Starting restore at 12-MAR-11

using channel ORA_DISK_1

channel ORA_DISK_1: restoring control file

channel ORA_DISK_1: restore complete, elapsed time: 00:00:02

output file name=/u01/oradata/control01.ctl

output file name=/u01/oradata/control02.ctl

output file name=/u01/oradata/control03.ctl

Finished restore at 12-MAR-11

5. 將資料庫啟動到mout狀態

SQL> alter database mount;

Database altered.

6. restore 資料庫

RMAN> restore database;

Starting restore at 12-MAR-11

released channel: ORA_DISK_1

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=20 device type=DISK

channel ORA_DISK_1: starting datafile backup set restore

channel ORA_DISK_1: specifying datafile(s) to restore from backup set

channel ORA_DISK_1: restoring datafile 00003 to /u01/app/oracle/oradata/dave/undotbs01.dbf

channel ORA_DISK_1: reading from backup piece /u01/backup/dave_lev0_28m70ar0_1_1_20110312

channel ORA_DISK_1: piece handle=/u01/backup/dave_lev0_28m70ar0_1_1_20110312 tag=DAVE_LEV0

channel ORA_DISK_1: restored backup piece 1

channel ORA_DISK_1: restore complete, elapsed time: 00:00:01

channel ORA_DISK_1: starting datafile backup set restore

channel ORA_DISK_1: specifying datafile(s) to restore from backup set

channel ORA_DISK_1: restoring datafile 00004 to /u01/app/oracle/oradata/dave/users01.dbf

channel ORA_DISK_1: reading from backup piece /u01/backup/dave_lev0_2am70ara_1_1_20110312

channel ORA_DISK_1: piece handle=/u01/backup/dave_lev0_2am70ara_1_1_20110312 tag=DAVE_LEV0

channel ORA_DISK_1: restored backup piece 1

channel ORA_DISK_1: restore complete, elapsed time: 00:00:01

channel ORA_DISK_1: starting datafile backup set restore

channel ORA_DISK_1: specifying datafile(s) to restore from backup set

channel ORA_DISK_1: restoring datafile 00002 to /u01/app/oracle/oradata/dave/sysaux01.dbf

channel ORA_DISK_1: reading from backup piece /u01/backup/dave_lev0_27m70ar0_1_1_20110312

channel ORA_DISK_1: piece handle=/u01/backup/dave_lev0_27m70ar0_1_1_20110312 tag=DAVE_LEV0

channel ORA_DISK_1: restored backup piece 1

channel ORA_DISK_1: restore complete, elapsed time: 00:00:25

channel ORA_DISK_1: starting datafile backup set restore

channel ORA_DISK_1: specifying datafile(s) to restore from backup set

channel ORA_DISK_1: restoring datafile 00001 to /u01/app/oracle/oradata/dave/system01.dbf

channel ORA_DISK_1: reading from backup piece /u01/backup/dave_lev0_26m70ar0_1_1_20110312

channel ORA_DISK_1: piece handle=/u01/backup/dave_lev0_26m70ar0_1_1_20110312 tag=DAVE_LEV0

channel ORA_DISK_1: restored backup piece 1

channel ORA_DISK_1: restore complete, elapsed time: 00:00:25

Finished restore at 12-MAR-11

7. recover 資料庫

RMAN> recover database;

Starting recover at 12-MAR-11

using channel ORA_DISK_1

starting media recovery

channel ORA_DISK_1: starting archived log restore to default destination

channel ORA_DISK_1: restoring archived log

archived log thread=1 sequence=24

channel ORA_DISK_1: reading from backup piece /u01/backup/arch_2cm70as8_1_1_20110312

channel ORA_DISK_1: piece handle=/u01/backup/arch_2cm70as8_1_1_20110312 tag=ARC_BAK

channel ORA_DISK_1: restored backup piece 1

channel ORA_DISK_1: restore complete, elapsed time: 00:00:01

archived log file name=/u01/app/oracle/product/11.2.0/dbhome_1/dbs/arch1_24_745352047.dbf thread=1 sequence=24

channel ORA_DISK_1: starting archived log restore to default destination

channel ORA_DISK_1: restoring archived log

archived log thread=1 sequence=25

channel ORA_DISK_1: reading from backup piece /u01/backup/arch_2dm70as8_1_1_20110312

channel ORA_DISK_1: piece handle=/u01/backup/arch_2dm70as8_1_1_20110312 tag=ARC_BAK

channel ORA_DISK_1: restored backup piece 1

channel ORA_DISK_1: restore complete, elapsed time: 00:00:01

archived log file name=/u01/app/oracle/product/11.2.0/dbhome_1/dbs/arch1_25_745352047.dbf thread=1 sequence=25

unable to find archived log

archived log thread=1 sequence=26

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of recover command at 03/12/2011 00:58:04

RMAN-06054: media recovery requesting unknown archived log for thread 1 with sequence 26 and starting SCN of 1055401

8. 在主庫進行一些事務操作

SQL> create table anhui as select * from all_tables;

Table created.

SQL> commit;

Commit complete.

SQL> alter system switch logfile;

System altered.

9. 關閉主庫，迅速把主庫的歸檔檔案和online redo 複製到Auxiliary庫

[oracle@qs-dmm-rh1 archivelog]$ scp * 192.168.2.43:/u01/archivelog

oracle@192.168.2.43's password:

1_26_745352047.dbf 100% 1509KB 1.5MB/s 00:00

[oracle@qs-dmm-rh1 dave]$ scp redo* 192.168.2.43:/u01/app/oracle/oradata/dave/

oracle@192.168.2.43's password:

redo01.log 100% 50MB 16.7MB/s 00:03

redo02.log 100% 50MB 12.5MB/s 00:04

redo03.log 100% 50MB 12.5MB/s 00:04

[oracle@qs-dmm-rh1 dave]$

10. 再次recover database

RMAN> recover database;

Starting recover at 12-MAR-11

using channel ORA_DISK_1

starting media recovery

archived log for thread 1 with sequence 26 is already on disk as file /u01/app/oracle/oradata/dave/redo02.log

archived log for thread 1 with sequence 27 is already on disk as file /u01/app/oracle/oradata/dave/redo03.log

archived log file name=/u01/app/oracle/oradata/dave/redo02.log thread=1 sequence=26

archived log file name=/u01/app/oracle/oradata/dave/redo03.log thread=1 sequence=27

media recovery complete, elapsed time: 00:00:05

Finished recover at 12-MAR-11

11. 開啟資料庫

SQL>alter database open resetlogs;

SQL> select count(*) from dave;

COUNT(*)

----------

71157

12. 重建Temp 表空間

在恢復的時候，會自動建立TEMP 表空間。但是和布豆聊到這個問題的時候，他說這個temp 檔案好像沒有起到作用。 尤其是資料量大的時候，所以他建議重建新增temp 資料檔案。

SQL> select name from v$tempfile;

NAME

--------------------------------------------------------------------------------

/u01/app/oracle/oradata/dave/temp01.dbf

SQL> alter tablespace temp add tempfile '/u01/app/oracle/oradata/dave/temp02.dbf ' size 8192M;

Tablespace altered.

SQL> select name from v$tempfile;

NAME

--------------------------------------------------------------------------------

/u01/app/oracle/oradata/dave/temp01.dbf

/u01/app/oracle/oradata/dave/temp02.dbf

SQL> alter database tempfile '/u01/app/oracle/oradata/dave/temp01.dbf' offline;

Database altered.

SQL> alter database tempfile '/u01/app/oracle/oradata/dave/temp01.dbf' drop including datafiles;

Database altered.

SQL> select name from v$tempfile;

NAME

--------------------------------------------------------------------------------

/u01/app/oracle/oradata/dave/temp02.dbf