Lenovo System x3300 M4 Installation And Service Manual page 60

– The following table lists the DIMM installation sequence for non-mirroring mode when one or two
microprocessors is installed in the server:
Table 9. DIMM population sequence (independent mode)
Number of installed
microprocessors
1
2
• Spare channel mode: When you use the memory mirroring feature, consider the following information:
– In spare channel mode, one rank is a spare of the other ranks on the same channel. The spare rank is
held in reserve and is not available as system memory. The spare rank must have identical or larger
memory capacity than all the other ranks (sparing source ranks) on the same channel. After sparing,
the sparing source rank will be lost.
– DIMMs must be installed in sets of three. The DIMMs in each set must be the same size and type.
– The following table lists the DIMM installation sequence for rank sparing mode when one or two
microprocessors is installed in the server:
Table 10. DIMM population sequence (rank sparing mode)
Number of installed
microprocessors
1
2
• Memory-mirroring mode: When you use the memory mirroring feature, consider the following
information:
– Memory-mirroring mode replicates and stores data on two pairs of DIMMs simultaneously. If a failure
occurs, the memory controller switches from the primary pair of memory DIMMs to the backup pair
of DIMMs. This mirroring provides redundancy in memory but reduces the total memory capacity to
one third. Channel 1 DIMM connectors 3, 4, 9, and 10 are not used in memory-mirroring mode. To
enable memory mirroring through the Setup utility, select System Settings ® Memory. For more
information, see "Using the Setup utility" on page 93.
– DIMMs must be installed in pairs. The DIMMs in each pair must be the same size and type.
– The maximum available memory is reduced to one third of the installed memory when memory
mirroring is enabled. For example, if you install 96 GB of memory, only 32 GB of addressable memory
is available when you use memory mirroring.
– The following table lists the DIMM installation sequence for memory-mirroring mode when one or
two microprocessors is installed in the server:
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System x3300 M4 Installation and Service Guide
DIMM connector population sequence
1, 3, 5, 2, 4, 6
1, 7, 3, 9, 5, 11, 2, 8, 4, 10, 6, 12
DIMM connector population sequence
1, 3, 5
2, 4, 6
1, 3, 5
7, 9, 11
2, 4, 6
8, 10, 12