Dropping Disks from a Disk Group

When you drop a disk from the disk group, the disk group is rebalanced by moving all of the file extents from the dropped disk to other disks in the disk group. Oracle ASM then releases the disk, and you can then add it to another disk group or use it for other purposes. You can drop one or multiple disks in a single operation. You can also optionally set rebalance power for the drop operation.

The following is a list of possible reasons for dropping a disk:

• A disk is starting to fail, and you must replace it.

• You want to upgrade a disk.

• You want to reallocate the disk to a different disk group, or reallocate the disk to a different storage system.

To drop one or more disks from a disk group:

1. Go to the Oracle ASM Home page.

   See "Accessing the Oracle Automatic Storage Management Home Page".

2. Click the Disk Groups link to display the Disk Groups subpage.

3. If the Oracle ASM Login page appears, then log in as the SYS user, connecting as SYSASM. Provide the SYS password that was set when the Oracle ASM instance was created.

4. Click a link in the Name column to select the disk group from which you want to drop disks.

   The Disk Group page appears.

5. Under the Member Disks heading, in the Select column, select the check boxes for the disks to drop, and then click Remove.

   A confirmation page appears.

6. To change rebalance power, or to set the FORCE option for dropping disks, do the following:

   1. Expand Show Advanced Options.

   2. Optionally select the Force option or select a value for rebalance power in the Rebalance Power list.

   Note: You may need the FORCE option if Oracle ASM cannot read from or write to the disk.

7. Click Yes to drop the disks.

   The Disk Group page returns, and displays a state of DROPPING for each disk being dropped.

8. Refresh the page until the dropped disks no longer appear in the disk group.