Oracle 12C ASM asmcmd amdu_extract

amdu_extract命令用来从磁盘组中抽取文件，其语法如下:

ASMCMD [+DATA/cs/DATAFILE] > help amdu_extract
amdu_extract
        Calls AMDU to extract 
<file>
  from 
 <disk group="">
  

Synopsis
        amdu_extract 
 </disk>
 <disk group=""> 
  <file> 
   <diskstring>
    

Description
        The options for amdu_extract command are described below:
        disk group - Name of the disk group containing the file to be extracted.        
        file       - Name of the file to be extracted. Can be specified as either an absolute or a relative path.
        diskstring - Specifies the value for the discovery diskstring.

Examples
        The following example uses amdu_extract to extract the parameter file from the '+datafile' 
        disk group.

        ASMCMD [+] > amdu_extract datafile +datafile/parameterfile/spfile.ora /devices/disk*


   </diskstring>
  </file>
 </disk>
</file>

其中diskgroup为被抽取文件所在的磁盘组名字，file_name，被抽取文件的Oracle ASM别名，disk_string为Oracle ASM发现磁盘字符串。而且amdu_extract实际是调用的AMDU工具来抽取文件

查询数据库cs的所有数据文件，这里我们要抽取的文件名是JY.331.976296525

ASMCMD [+DATA/cs/DATAFILE] > ls -lrt
WARNING:option 'r' is deprecated for 'ls'
please use 'reverse'

Type      Redund  Striped  Time             Sys  Name
DATAFILE  UNPROT  COARSE   MAR 12 18:00:00  Y    SYSAUX.259.970598293
DATAFILE  UNPROT  COARSE   MAR 12 18:00:00  Y    SYSTEM.258.970598233
DATAFILE  UNPROT  COARSE   MAR 12 18:00:00  Y    UNDOTBS1.260.970598319
DATAFILE  UNPROT  COARSE   MAR 12 18:00:00  Y    USERS.261.970598319
DATAFILE  UNPROT  COARSE   AUG 16 11:00:00  Y    JY.331.976296525
DATAFILE  UNPROT  COARSE   AUG 16 11:00:00  Y    SYSAUX.273.970601881
DATAFILE  UNPROT  COARSE   AUG 16 11:00:00  Y    SYSTEM.272.970601831
DATAFILE  UNPROT  COARSE   AUG 16 11:00:00  Y    TEST.326.976211663
DATAFILE  UNPROT  COARSE   AUG 16 11:00:00  Y    UNDOTBS1.274.970601905
DATAFILE  UNPROT  COARSE   AUG 16 11:00:00  Y    UNDOTBS2.284.970602381
DATAFILE  UNPROT  COARSE   AUG 16 11:00:00  Y    USERS.275.970601909

SQL> select name,file_number from v$asm_alias where file_number<>4294967295 and (name like '%jy%' or name like '%JY%');

NAME                                                                                                                                         FILE_NUMBER
-------------------------------------------------------------------------------------------------------------------------------------------- -----------
JY.331.976296525                                                                                                                                     331

ASMCMD [+DATA/cs/DATAFILE] > amdu_extract DATA +DATA/cs/DATAFILE/JY.331.976296525 /dev/asm*
ASMCMD-8024: file number could not be determined for alias name '+DATA/cs/DATAFILE/JY.331.976296525' 
< ?pre>
可以看到提示信息说通过文件别名不能判断文件号，实际上+DATA/cs/DATAFILE/JY.331.976296525是Oracle在ASM中创建的数据文件名，并不是别名。如是我们来手动为+DATA/cs/DATAFILE/JY.331.976296525增加别名jy01.dbf

SQL> alter diskgroup data add alias '+DATA/cs/DATAFILE/jy01.dbf' for '+DATA/cs/DATAFILE/JY.331.976296525';

Diskgroup altered.


SQL> select name,file_number from v$asm_alias where file_number<>4294967295 and (name like '%jy%' or name like '%JY%');

NAME                                                                                                                                         FILE_NUMBER
-------------------------------------------------------------------------------------------------------------------------------------------- -----------
JY.331.976296525                                                                                                                                     331
jy01.dbf                                                                                                                                             331

ASMCMD [+DATA/cs/DATAFILE] > amdu_extract DATA +DATA/cs/DATAFILE/jy01.dbf /dev/asm*
amdu_2018_08_16_19_17_42/

[grid@cs1 ~]$ ls -lrt

drwxr-xr-x 2 grid oinstall     40 Aug 16 19:17 amdu_2018_08_16_19_17_42
[grid@cs1 ~]$ cd amdu_2018_08_16_19_17_42
[grid@cs1 amdu_2018_08_16_19_17_42]$ ls -lrt
total 102416
-rw-r--r-- 1 grid oinstall      8103 Aug 16 19:17 report.txt
-rw-r--r-- 1 grid oinstall 104865792 Aug 16 19:17 DATA_331.f

使用amdu工具来抽取数据文件是指定Oracle ASM发现磁盘字符串和磁盘组.数据文件序号

[grid@cs2 ~]$ amdu -diskstring '/dev/asm*' -extract 'DATA.331'
amdu_2018_08_16_19_20_59/
AMDU-00204: Disk N0004 is in currently mounted diskgroup DATA.
AMDU-00201: Disk N0004: '/dev/asmdisk04'
[grid@cs2 ~]$ cd amdu_2018_08_16_19_20_59/
[grid@cs2 amdu_2018_08_16_19_20_59]$ ls -lrt
total 102420
-rw-r--r-- 1 grid oinstall      8291 Aug 16 19:21 report.txt
-rw-r--r-- 1 grid oinstall 104865792 Aug 16 19:21 DATA_331.f

可以看到使用amdu与asmcmd的amdu_extract所抽取的同一个文件大小都是104865792。