2.2.7 Dropping a Disk from an Oracle ASM Disk Group

You can drop a grid disk from a disk group.

1. Determine which disks you want to drop from the Oracle ASM disk group.

   Query the V$ASM_DISK and V$ASM_DISKGROUP views on the Oracle ASM instance.

   If you are removing an Oracle Exadata Storage Server grid disk, then ensure that you identify the grid disks that are mapped to each Oracle ASM disk group.

2. Use the SQL ALTER DISKGROUP command with the DROP DISK clause to drop the disks from the Oracle ASM disk group.

   SQL> ALTER DISKGROUP disk_group_name 
   DROP DISK data_CD_11_cell01 NORMAL;

   Do not use the FORCE option when dropping the disk from the Oracle ASM disk group. If you use the FORCE option, Oracle Exadata System Software will attempt to add the disk back to the disk group if the disk online automation operation is triggered, by rebooting the storage server, for example. See Enhanced Manageability Features in Oracle Exadata Database Machine System Overview.

When the disk is dropped from the Oracle ASM disk group, Oracle ASM rebalances the disk group. Oracle ASM monitors the rebalance operation, and Oracle Exadata System Software sends an e-mail message when the operation is complete.

You can query the V$ASM_OPERATION view for the status of the rebalance operation.

After an Oracle Exadata Storage Server grid disk is dropped from the Oracle ASM disk group, you can drop the grid disk from the cell.