“- For mount a diskgroup,(This is instance specific, for mounting on all nodes, run the same on all nodes) SQL>alter diskgroup DATA mount;  or asmcmd>mount DATA -- For umount a diskgroup,(This is instance specific, for unmounting on all nodes, run the same on all nodes) SQL>alter diskgroup DATA dismount; Or asmcmd>umount DATA -- To mount/Dismount all the diskgroups SQL>alter diskgroup ALL mount;  SQL>alter diskgroup ALL dismount;”