priority servers may get less power than priority-one servers based onSystem Input Max Power Capacity, and the user-configured setting ofSystem Input Power Cap.Configuration changes, such as an additional server, shared HDDs, or PCIe cards in the chassis, may require theSystemInput Power Cap to be increased. Power needs in a modular enclosure also increase when thermal conditions changeand the fans are required to run at higher speed, which causes them to consume additional power. Insertion of I/Omodule and storage adapters, PCIe cards, physical disk, main board; number, type, and configuration of PSUs alsoincrease the power needs of the modular enclosure. A fairly small amount of power is consumed by servers even whenthey are powered down to keep the management controller powered up.Additional servers can be powered up in the modular enclosure only if sufficient power is available. TheSystem InputPower Cap can be increased any time up to a maximum value of 5000 Watt to allow the power up of additional servers.Changes in the modular enclosure that reduce the power allocation are:• Server turned off• I/O module turned off• Storage adapters, PCIe cards, physical disk drive, and main board turned off• Transition of the chassis to a turned-off stateYou can reconfigure theSystem Input Power Cap when the chassis is either turned on or turned off.Server Slot Power Priority SettingsCMC allows you to set a power priority for each of the four server slots in an enclosure. The priority settings are 1(highest) through 9 (lowest). These settings are assigned to slots in the chassis, and the priority of the slots is inheritedby any server inserted in that slot. CMC uses slot priority to preferentially budget power to the highest priority servers inthe enclosure.According to the default server slot priority setting, power is equally apportioned to all slots. Changing the slot prioritiesallows administrators to prioritize the servers that are given preference for power allocations. If the more critical servermodules are left at their default slot priority of 1, and the less critical server modules are changed to lower priority valueof 2 or higher, the priority 1 server modules is powered on first. These higher priority servers get their maximum powerallocation, while lower priority servers may be not be allocated enough power to run at their maximum performance orthey may not even power on at all, depending on how low the system input power cap is set and the server powerrequirements.If an administrator manually powers on the low priority server modules before the higher priority ones, then the lowpriority server modules are the first modules to have their power allocation lowered down to the minimum value, in orderto accommodate the higher priority servers. Therefore, after the available power for allocation is exhausted, CMCreclaims power from lower or equal priority servers until they are at their minimum power level.NOTE: I/O module, fans, and mainboard, physical disk drives, storage adapters are given the highest priority. CMCreclaims power only from the lower-priority devices to meet the power needs of a higher-priority device or server.Assigning Priority Levels To ServersWhen additional power is required, server priority levels determine which servers the CMC draws power from.NOTE: The priority you assign to a server is linked to a server's slot and not to the server itself. If you move theserver to a new slot, you must re-configure the priority for the new slot location.NOTE: To perform power management actions, you must have the Chassis Configuration Administrator privilege.149
