Table 8. DIMM connectors on each memory channelNumber of installedmicroprocessors Memory channel DIMM connectorsMicroprocessor 2Channel 1 15, 16Channel 2 13, 14Channel 3 9, 10Channel 4 11, 12Memory mirroringMemory-mirroring mode replicates and stores data on two pairs of DIMMs withintwo channels simultaneously.About this taskMemory-mirroring mode replicates and stores data on two pairs of DIMMs withintwo channels simultaneously. If a failure occurs, the memory controller switchesfrom the primary pair of memory DIMMs to the backup pair of DIMMs. You mustenable memory mirroring through the Setup utility. For details about enablingmemory mirroring, see “Using the Setup utility” on page 91. When you use thememory mirroring feature, consider the following information:v DIMMs must be installed in pairs. The DIMMs in each pair must be the samesize and type.v The maximum available memory is reduced to one third of the installedmemory when memory mirroring is enabled. For example, if you install 96 GBof memory, only 32 GB of addressable memory is available when you usememory mirroring.v Channel 1 DIMM connectors 1, 2, 7, and 8 are not used in memory-mirroringmode.The following table lists the installation sequence for installing DIMMs inmemory-mirroring mode.Table 9. DIMM population sequence (memory-mirroring mode)Number of installed microprocessors DIMM connector population sequence18, 61, 37, 52, 428, 6, 16, 141, 3, 9, 117, 5, 15, 132, 4, 10, 12When 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.Chapter 2. Installing optional devices 63