Datasheet

Working with the ASM Instance 21
contents clause. The drop diskgroup statement is synchronous in nature, so once the prompt
returns, the deed is done … no Recycle Bin here. When the
drop diskgroup command is exe-
cuted, ASM will unmount the disk from the ASM instance and write over all the ASM-related
information on that disk. The
ASM_DISKGROUPS parameter will also be changed if you are
using an spfile. Here is an example of removing an ASM disk group with the
drop diskgroup
command:
Drop diskgroup sp_dgroup2;
If the ASM disk group has files in it, use this version:
Drop diskgroup sp_dgroup2 including contents;
Altering an ASM Disk Group
The alter diskgroup command is used to modify ASM disk groups. With the alter
diskgroup
command, you can do the following:
Add disks to an ASM disk group

Remove disks from an ASM disk group

Add and drop disks from an ASM disk group

Undrop disks from an ASM disk group

Resize disks in a disk group

Manually rebalance a disk group

Mount and unmount disk groups

Check the consistency of a disk group

Create ASM disk group directories

Manage ASM disk group directories

Adding Disks to an ASM Disk Group
As databases grow, you need to add disk space. The alter diskgroup command allows
you to add disks to a given disk group to increase the amount of space available. Adding
a disk to an existing disk group is easy with the
alter diskgroup command, as shown in
this example:
alter diskgroup cooked_dgroup1
add disk ‘c:\oracle\asm_disk\_file_disk3’
name new_disk;
When you add a disk to a disk group, Oracle will start to rebalance the load on that
disk group. Also, notice that in the preceding example we did not assign the disk to a
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