IBM Power Systems 775 Manual

Contents

Chapter 1. Understanding the IBM Power Systems 775 Cluster 43One per BPCE for populations of one to three BPRs/BPCE and two per BPCE for four tosix BPRs/BPCE.The front and rear views of the BPCA are shown in Figure 1-33.Figure 1-33 BPCAThe minimum configuration per BPCE is one x BPCH, one x BPD, one x BPR and one linecore. There are always two BPCAs above one another in the top of the cabinet.BPRs are added uniformly to each BPCE depending on the power load in the rack.A single fully configured BPCE provides 27 KW x 6 = 162 KW of Bulk Power, which equatesto aggregate system power cord power of approximately 170 KW. Up to this power level, bulkpower is in a 2N arrangement, where a single BPCE is removed entirely for maintenanceconcurrently with the rack that remains fully operational. If the rack bulk power demandexceeds 162 KW, the bulk power provides an N+1 configuration of up to 27 KW x 9 = 243 KW,which equates to aggregate system power cord power of approximately 260 KW. N+1 BulkPower mode means one of the four power cords are disconnected and the cabinet continuesto operate normally. BPCE concurrent maintenance is not conducted in N+1 bulk powermode, unless the rack bulk power load is reduced to less than 162 KW by invoking PowerEfficient Mode on the server nodes. This mode reduces the peak power demand at theexpense of reducing performance.CoolingThe BPCA is nearly entirely water cooled. Each BPR and the BPD has two quick connects toenable connection to the supply and return water cooling manifolds in the cabinet. All of thecomponents that dissipate any significant power in the BPR and BPD are heat sunk to awater-cooled cold plate in these units.To assure the ambient air temperature internal to the BP, BPCH, and BPD enclosures is keptlow, two hot pluggable blowers are installed in the rear of each BPCA in an N+1 speedcontrolled arrangement. These blowers flush the units to keep the temperature internal atapproximately system inlet air temperature, which is 40 degrees-C maximum. A fan isreplaced concurrently.BPFBPFBPF BPFBPEBPRBPR BPDBPCHFront ViewRear ViewLine Cord ConnectorLine Cord Connector