Prior to Oracle Database 11g Release 2, you had to issue the following commands in sqlplus to mount and dismount a diskgroup:

 
SQL> alter diskgroup fra mount;

Diskgroup altered.

SQL> alter diskgroup fra dismount;

Diskgroup altered.

As of Oracle Database 11g Release 2, an easier and more SA friendly approach is provided with asmcmd:

 
ASMCMD> mount fra

Looking at the disk group information with the lsdg command, we see that the fra disk group is now mounted:

 
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  EXTERN  N         512   4096  1048576     15640     5352                0            5352              0             N  DATA/
MOUNTED  EXTERN  N         512   4096  1048576     45792    45736                0           45736              0             N  DG_EXTERNAL/
MOUNTED  EXTERN  N         512   4096  1048576     42068    42016                0           42016              0             N  FRA/

Let’s issue the umount command in asmcmd. Notice that the syntax is umount in asmcmd and dismount in SQL*Plus:

 
ASMCMD> umount fra

Looking at the disk group information with the lsdg command, we see that the fra disk group is no longer mounted:

 
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  EXTERN  N         512   4096  1048576     15640     5352                0            5352              0             N  DATA/
MOUNTED  EXTERN  N         512   4096  1048576     45792    45736                0           45736              0             N  DG_EXTERNAL/

Posted by Charles Kim, Oracle ACE

Posted in ASM
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