Mounting Disk Groups Using the FORCE Option

In the FORCE mode, ASM attempts to mount the disk group even if it cannot discover all of the devices that belong to the disk group. This setting is useful if some of the disks in a normal or high redundancy disk group became unavailable while the disk group was dismounted.

If ASM discovers all of the disks in the disk group, then MOUNT FORCE fails. Therefore, use the MOUNT FORCE setting only if some disks are unavailable. Otherwise, use NOFORCE [the default].

The disk group

mount succeeds if ASM finds at least one complete set of extents in a

disk group. If ASM determines that one or more disks are not

available, then ASM moves those disks off line and drops [sic!] the disks

after the DISK_REPAIR_TIME expires.

In clustered ASM environments, if an ASM instance is not the first instance to mount the disk group, then using the MOUNT FORCE statement fails. This is because the disks have been accessed by another instance and the disks are not locally accessible.