理解ASM（六）ASM檔案管理

① ASM檔案轉化

以建立的asmtest資料表空間為例

㈠ 將os檔案轉換為ASM檔案

sys@ORCL> create tablespace asmtest datafile size 10m;

Tablespace created.

sys@ORCL> alter tablespace asmtest offline;

Tablespace altered.

[oracle@localhost ~]$ rman target /

RMAN> backup as copy tablespace asmtest format '+DATA';

RMAN> switch tablespace asmtest to copy;

datafile 6 switched to datafile copy "+DATA/orcl/datafile/asmtest.256.798497595"

sys@ORCL> alter tablespace asmtest online;

Tablespace altered.

sys@ORCL> select file_name from dba_data_files where tablespace_name='ASMTEST';

FILE_NAME

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

+DATA/orcl/datafile/asmtest.256.798497595

ASMCMD> mkalias ASMTEST.256.798497595 asmtest.dbf

ASMCMD> ls -al

Type Redund Striped Time Sys Name

DATAFILE MIRROR COARSE NOV 04 20:00:00 Y +DATA/ORCL/DATAFILE/asmtest.dbf => ASMTEST.256.798497595

N asmtest.dbf => +DATA/ORCL/DATAFILE/ASMTEST.256.798497595

㈡ 將資料檔案從一個diskgroup遷移到另一個diskgroup

idle> select file_id from dba_data_files where tablespace_name='ASMTEST';

FILE_ID

----------

6

idle> alter tablespace asmtest offline;

[oracle@localhost ~]$ rman target /

RMAN> backup as copy datafile 6 format '+THINK';

RMAN> switch datafile 6 to copy;

RMAN> recover datafile 6;

RMAN> sql "alter tablespace asmtest online";

ASMCMD> find THINK/ *

+THINK/ORCL/

+THINK/ORCL/DATAFILE/

+THINK/ORCL/DATAFILE/ASMTEST.256.798503425

㈢ 將ASM檔案轉寄成OS檔案

sys@ORCL> select file_name from dba_data_files where tablespace_name='ASMTEST';

FILE_NAME

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

+THINK/orcl/datafile/asmtest.256.798503425

sys@ORCL> alter tablespace asmtest offline;

sys@ORCL> create directory ossrc as '/home/oracle';

sys@ORCL> create directory asmsrc as '+THINK/orcl/datafile';

sys@ORCL> begin

2 dbms_file_transfer.copy_file('ASMSRC','ASMTEST.256.798503425','OSSRC','ASM.DBF');

3 end;

4 /

PL/SQL procedure successfully completed.

sys@ORCL> alter database rename file '+THINK/orcl/datafile/asmtest.256.798503425' to '/home/oracle/ASM.DBF';

[oracle@localhost ~]$ rman target /

RMAN> recover datafile 6;

RMAN> sql "alter tablespace asmtest online";

sys@ORCL> select file_name from dba_data_files where tablespace_name='ASMTEST';

FILE_NAME

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

/home/oracle/ASM.DBF

② ASM中的檔案名稱

ASM檔案名稱，諸如：

+THINK/orcl/datafile/asmtest.256.798503425

上述名稱的產生格式為：

+diskgroup/dbname/file_type/file_type_tag.file.incarnation

● +diskgroup ：磁碟組名稱

● dbname ：資料庫的DB_UNIQUE_NAME參數值

● file_type ：建立的檔案類型，比如CONTROLFILE/DATAFILE/ONLINELOG/ARCHIVELOG/TEMPFILE/BACKUPSET/FLASHBACK等等

● file_type_tag ：檔案類型的標籤，比如資料表空間對應的通常為該資料表空間名稱

● file.incarnation ：檔案序號+incarnation，用來確保檔案的唯一

檔案建立時無法指定實際檔案名稱及路徑，完全由ORACLE的OMF控制和管理

例如：

sys@ORCL> alter tablespace asmtest add datafile '+DATA' size 10m;

Tablespace altered.

如果設定了初始化參數db_create_file_dest，甚至連磁碟組名都不需要寫了

其它類型檔案，比如重做記錄檔等，操作方式都是同理的

但像trace檔案、alert檔案、dump檔案等還不能直接被儲存到ASM中

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