The following table lists the installation sequence for installing DIMMs inmemory-mirroring mode.Table 10. Memory-mirroring mode DIMM population sequenceDIMMsNumber of installedmicroprocessors DIMM connectorFirst pair of DIMMs 1 3, 6Second pair of DIMMs 1 2, 5Third pair of DIMMs 1 1, 4Fourth pair of DIMMs 2 12, 15Fifth pair of DIMMs 2 11, 14Sixth pair of DIMMs 2 10, 13Note: DIMM connectors 7, 8, 9, 16, 17, and 18 are not used in memory-mirroring mode.When you install or remove DIMMs, the server configuration information changes.When you restart the server, the system displays a message that indicates that thememory configuration has changed.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 144). When youuse 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 three DIMMsper microprocessor at a time. The first DIMM must be in channel 0, the secondDIMM in channel 1, and the online-spare DIMM in channel 2. The DIMMs mustbe identical in size, type, rank, and organization, but not in speed. The channelsrun 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 memory whenmemory online-spare mode is enabled. For example, if you install 72 GB ofmemory using RDIMMs, only 48 GB of addressable memory is available whenyou 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 11. 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, 16Chapter 2. Installing optional devices 109
