Dropping Disks from Disk Groups

When you drop a disk from a disk group, Oracle ASM rebalances the disk group 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 the disk to another disk group or use it for other purposes. You can drop one or more 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

  • To upgrade a disk

  • To reallocate the disk to a different disk group or reallocate the disk to a different storage system

Note:

Dropping disks from a disk group only logically deletes the disks from the disk group. It does not delete the disk contents. However, the contents are lost when you add the disk to a new disk group.

To drop one or more disks from a disk group:

  1. Access the Oracle Automatic Storage Management home page.

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

  2. Click the Disk Groups link to display the Disk Groups property page.

  3. If the Oracle Automatic Storage Management Login page appears, log in as the SYS user, connecting as SYSASM. Provide the SYS password for the Oracle ASM instance. This password was set up when the Oracle ASM instance was created.

  4. Click a link in the Name column to select the disk group that contains the disks to be dropped.

    The Disk Group page appears.

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

    A confirmation page appears.

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

    1. Click Show Advanced Options.

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

    Note:

    You might need the FORCE option if Oracle ASM cannot read from or write to the disk. For a discussion of the FORCE option, see "Dropping Disks from Disk Groups".

  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.

Caution:

You cannot reuse or disconnect the dropped disks until the drop and rebalance operations are complete. Operations are complete when the dropped disks no longer appear in the disk group. For more information about dropping disks, see "Dropping Disks from Disk Groups".