Mounting and Dismounting Disk Groups

Mounting and DismountingDisk Groups

Disk groups that are specified in the

ASM_DISKGROUPS

initialization parameter are mounted automatically at ASM instancestartup. This makes them available to all database instancesrunning on the same node as ASM. The diskgroups are dismounted atASM instance shutdown. ASM also automatically mounts a diskgroup when you initially create it, and dismounts a disk group ifyou drop it.There may be times that you want to mount or dismount diskgroups manually. For these actions use the

ALTERDISKGROUP...MOUNT

or

ALTER DISKGROUP...DISMOUNT

statement. You can mount or dismount disk groups by name, orspecify

ALL

.If you try to dismount a disk group that contains openfiles, the statement will fail, unless you also specify the

FORCE

clause.DismountingDisk Groups: ExampleThe following statement dismounts all disk groups thatare currently mounted to the ASM instance:

ALTER DISKGROUP ALL DISMOUNT;

Mounting Disk Groups:ExampleThe following statement mounts disk group

dgroup1

:

ALTER DISKGROUP dgroup1 MOUNT;

地址：http://docs.oracle.com/cd/B19306_01/server.102/b14200/statements_1006.htm#i2168824

diskgroup_availability::=

diskgroup_availabilityUse this clause to make one or more diskgroups available or unavailable to the database instances runningon the same node as the Automatic Storage Management instance.---使用这个语句能确保一个或者多个磁盘组队ASM实例同一个节点的数据库实例的可用或者不可用。Thisclause does not affect the status of the disk group on other nodesin a cluster.---这个子句并不会影响在集群里头的其他节点。MOUNT Specify

MOUNT

to mount the disk groups in the local AutomaticStorage Management instance. Specify

ALL

MOUNT

to mount all disk groups specified in the

ASM_DISKGROUPS

initialization parameter. Fileoperations can only be performed when a disk group ismounted.See Also:

ASM_DISKGROUPS

for more information about adding disk group names to theinitialization parameter file

DISMOUNT Specify [code]DISMOUNT

to dismount the specified disk groups. Automatic Storage Management returns an error if any file in the disk group is open unless you also specify

FORCE

. Specify

ALL

DISMOUNT

to dismount all currently mounted disk groups. File operations can only be performed when a disk group is mounted.FORCE Specify

FORCE

if you want Automatic Storage Management to dismount the disks even if some files in the disk group are open.[/code]