Mounting and Dismounting a Diskgroup

Diskgroups are automatically mounted at ASM instance startup and dismounted at ASM instance shutdown. To manually mount and dismount the diskgroups use the following statements,

Syntax:

ALTER DISKGROUP ALL or diskgroup_name MOUNT or DISMOUNT;

Example 1 (Mount a specific diskgroup)

SQL> Alter Diskgroup ASMIND Mount;

Example 2 (Dismount all diskgroups)

SQL> Alter Disgroup ALL DisMount;

Note

In the case of High and Normal Redundancy diskgroups you need all set of extents available for the diskgroups to mount. The unavailable disks may be used for redundant copies and you may mount the diskgroups without those disks. If there are sufficient disks available for the diskgroups to mount you can use the force option to mount it.

Alter Diskgroup diskgroup_name Mount Force;

The unavailable disks are taken offline. ASM drops those disks after the DISK_REPAIR_TIME expires.

In RAC ASM environments, you cannot MOUNT FORCE a disk group that is already mounted by another instance because the disks have been accessed by another instance and the disks are not locally accessible.

Thanks