If you want to know which multipath device maps to which ASMlib configured disk, you can use this command:
find /dev/mapper/ -exec '/etc/init.d/oracleasm' 'querydisk' '{}' ';'
To get ASM disks only, grep output for "is marked an ASM disk"
#oratidbit#OracleASM You can upgrade Oracle ASM 11g 11.2 and later without shutting down an Oracle RAC database by performing a rolling upgrade either of individual nodes, or of a set of nodes in the cluster.