IBM 7944, Installation And User Manual

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CPU1
CPU2
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10
9
1 1 2 2 3 3
4 4 5 5 6 6
17 18
Figure 31. Memory connectors associated with each microprocessor for memory mirroring
The following table shows the installation sequence for installing DIMMs in memory-mirroring mode:
Table 12. Memory mirroring mode DIMM population sequence
Number of DIMMs
Number of installed
microprocessor
DIMM connector
First pair of DIMMs 1 3, 6
Second pair of DIMMs
1 2, 5
Third pair of DIMMs 1 1, 4
Fourth pair of DIMMs 2 12, 15
Fifth pair of DIMMs 2 11, 14
Sixth pair of DIMMs 2 10, 13
DIMM connectors 7, 8, 9, 16, 17, and 18 are not used in memory-mirroring mode.
Online-spare memory
The memory online-spare feature disables the failed memory from the system configuration and activates an
online-spare DIMM to replace the failed active DIMM.
You can enable either online-spare memory or memory mirroring in the Setup utility (see “Using the Setup
utility” on page 106 ). When you use the memory online-spare feature, consider the following information:
• The memory online-spare feature is supported on server models with an Intel Xeon™ 5600 series
microprocessor.
• When you enable the memory online-spare feature, you must install three DIMMs per microprocessor at a
time. The first DIMM must be in channel 0, the second DIMM in channel 1, and the third DIMM in channel
2. The DIMMs 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.
• The maximum available memory is reduced to 2/3 of the installed memory when memory online-spare
mode is enabled. For example, if you install 72 GB of memory using RDIMMs, only 48 GB of addressable
memory is available when you use memory online-spare.
The following table shows the installation sequence for installing DIMMs for each microprocessor in memory
online-spare mode:
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System x3550 M3Installation and User's Guide