User Guide178www.nec-computers.comOnline Spare MemoryThe online memory spare feature puts a group of memory devices within a memorybranch into standby status as spare devices. If an unrecoverable error occurs in aDIMM of the running group, the feature automatically changes the running DIMMfrom the failed one to a DIMM in the standby group to continue the processing.Figure 92: Online Spare MemoryA: MotherboardB: Memory ControllerC: Branch #0D: Branch #1E: In OperationF: StandbysNote: The operating system recognizes the memorydevices as those with capacities less than the actual physicalcapacities. (The recognized capacities vary depending on thenumber of DIMMs and the physical capacity per DIMM.)The online spare memory feature can be used under the following conditions:■ Install memory devices to more than one group in each memory branch. The servercan operate even if the memory branches are different in the number of DIMMs.For example, no error occurs if memory branches 0 and 1 include four DIMMs (ortwo groups) and six DIMMs (or three groups), respectively.ABC D#1 #2#3 #4#5 #6EF
