Online-spare memoryThe server supports online-spare memory. This feature disables the failed memoryfrom the system configuration and activates an online-spare DIMM to replace thefailed active DIMM. You can enable either online-spare memory or memorymirroring in the Setup utility (see “Using the Setup utility” on page 158). Whenyou use the memory online-spare feature, consider the following information:v The memory online-spare feature is supported on server models with an IntelXeon ™ 5600 series microprocessor.v When you enable the memory online-spare feature, you must install threeDIMMs per microprocessor at a time. The first DIMM must be in channel 0, thesecond DIMM in channel 1, and the online-spare DIMM in channel 2. TheDIMMs must be identical in size, type, rank, and organization, but not in speed.The channels run at the speed of the slowest DIMM in any of the channels.v The maximum available memory is reduced to 2/3 of the installed memorywhen memory online-spare mode is enabled. For example, if you install 72 GBof memory using RDIMMs, only 48 GB of addressable memory is availablewhen you use memory online-spare.The following table shows the installation sequence for installing DIMMs for eachmicroprocessor and the online-spare DIMM in memory online-spare mode:Table 13. Memory online-spare mode DIMM population sequenceInstalledMicroprocessor DIMM connectorMicroprocessor 1 3, 6, 93, 6, 9, 2, 5, 83, 6, 9, 2, 5, 8, 1, 4, 7Microprocessor 2 12, 15, 18,12, 15, 18, 11, 14, 17,12, 15, 18, 11, 14, 17, 10, 13, 16Installing a DIMMAbout this taskTo install a DIMM, complete the following steps.Chapter 2. Installing optional devices 121
