Use the FORCE option to mount a disk group when there are missing disks or missing failure groups. The FORCE option corrects configuration errors, such as incorrect values for ASM_DISKSTRING, without incurring unnecessary rebalance operations. Disk groups mounted with the FORCE option have one or more disks offline if the disks were not available at the time of the mount. You must take corrective action to restore those devices before the time set with the DISK_REPAIR_TIME value expires. Failing to restore and put those disks back online within the disk repair time frame results in Oracle ASM automatically removing the disks from the disk group. This would then require a rebalance operation to restore redundancy for all of the files in the disk group. Perform the following procedures to mount a disk with the FORCE option:
From the Oracle ASM home page click the Disk Groups tab.
Select the disk group that has a disk that you must repair and click Dismount. Click OK on the Dismount confirmation dialog. The State column of the Disk Group home page should show the Status as DISMOUNTED.
Perform any needed repairs to the disk in the disk group.
Click the box in the Select column next to the disk that you plan to force mount, then click Mount.
On the Disk Mount Confirmation dialog, click the Show Advanced Options link.
On the Mount Force Confirmation dialog, select the Force option and click Yes. You can also click No to cancel the mount force operation and Show SQL to review the SQL that Oracle Enterprise Manager uses to perform the mount force operation.