Abstract: A method and system is provided where once the disk array subsystem has been initialized and mapped, addition and deletion of logical drives will be made without interruption to system operation. In adding a logical device, a method is provided to determine the amount of space required in adding the new logical device and the amount of physical space available for such operation. In adding such a new logical device, the data of the new logical device may be placed anywhere on the physical drives. In deleting a logical device, the space made available when deleting the data of the logical device creates a physical gap to the original mapping where the gap could be filled by subsequent additions of new logical devices. Once a new mapping is determined, the mapping is sent to the adapters and device controllers to update the mapping information available to the adapters and the device controllers in order for the adapters and the device controllers to properly address data in the disk array subsystem.