For each of the asm volumes execute the command:
/etc/init.d/oracleasm createdisk ASMn /dev/mapper/ASMnp1

Replacing the “n” with the relevant numbers.

N.B. It is important that the mapping is made to the partion space (e.g. asm1p1) and NOT asm1 for the multipath devices as this would overwrite the volume header and remove the partition.

Perform the following on all nodes in the cluster:

# /etc/init.d/oracleasm scandisks
# /etc/init.d/oracleasm listdisks

The ASM volumes should now be listed in the directory /dev/oracleasm/disks

# ls /dev/oracleasm/disks
ASM1     ASM2    ASM3 etc