ORA-15428
Invalid disk slots to enable appliance mode.
Cause
Appliance mode requires that the set of disk slots in every regular (non-quorum) failure group is the same and also, the disk slots are consecutive.
Action
Use cellcli and check the celldisk attribute 'virtualslot' for every disk that belongs to the Oracle Automatic Storage Management (Oracle ASM) disk group. Ensure the slot requirements are met before enabling appliance mode for the disk group. If this is CREATE DISKGROUP operation, ensure that the correct set of disks are used. Otherwise, use the ALTER DISKGROUP SQL to ADD the correct disks to the disk group or DROP the incorrect disks from the disk group.