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