In a SPARC M8-8 or a SPARC M7-8 server that is configured with a single PDomain, there are eight CMIOUs in the PDomain. Each CMIOU chassis has two redundant SPs. To facilitate failover from one SP to another, one SP serves as the Active SP, and one serves as the Standby SP. The Active SP manages system resources unless it can no longer do so, in which case the Standby SP assumes its role.