IBM System x3750 M4 Type 8733, Installation And Service Manual

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mode, see “Non-mirroring (independent mode).” For more information and
DIMM population for memory mirroring, see “Memory mirroring.” For more
information and DIMM population for memory sparing, see “Memory sparing”
on page 45.
Non-mirroring (independent mode)
When you use non-mirroring mode, follow the DIMM population sequence as
indicated in the following table..
Note: When you install an optional microprocessor and memory expansion tray in
the server, microprocessors 3 and 4 must be installed as a pair. The server does not
support a configuration of three microprocessors.
Table 8. DIMM population sequence for non-mirroring mode (independent mode)
Number of
installed
microprocessors
DIMM connector population
sequence on the system board
DIMM connector population
sequence on the microprocessor
and memory expansion tray
1 1, 12, 4, 9, 2, 11, 5, 8, 3, 10, 6, 7
2 1, 13, 12, 24, 4, 16, 9, 21, 2, 14, 11,
23, 5, 17, 8, 20, 3, 15, 10, 22, 6, 18, 7,
19
4 1, 13, 12, 24, 4, 16, 9, 21, 2, 14, 11,
23, 5, 17, 8, 20, 3, 15, 10, 22, 6, 18, 7,
19 25, 37, 36, 48, 28, 40, 33, 45, 26, 38,
35, 47, 29, 41, 32, 44, 27, 39, 34, 46,
30, 42, 31, 43
Memory mirroring
Memory-mirroring replicates and stores data on DIMMs across two or four
channels simultaneously. If a failure occurs, the memory controller switches from
the DIMMs on the primary channel to the DIMMs on the backup channel. To
enable memory mirroring through the Setup utility, select
System Settings
→
Memory
→
Memory Mode . For more information, see “Using the Setup utility” on
page 127.
When you use memory mirroring mode, consider the following information:
v
The server supports single-socket memory mirroring. Memory channel 0 mirrors
channel 1, and memory channel 2 mirrors channel 3. This mirroring provides
redundancy in memory but reduces the total memory capacity in half.
v
DIMMs must be installed in pairs for each microprocessor when using the
memory mirroring feature.
v
The DIMM population must be identical for memory channel 0 and memory
channel 1, and identical for memory channel 2 and memory channel 3.
v
Memory mirroring reduces the maximum available memory by half of the
installed memory. For example, if the server has 64 GB of installed memory, only
32 GB of addressable memory is available when memory mirroring is enabled.
v
The following table lists the DIMM installation sequence for memory-mirroring
mode.
Note: The server does not support a configuration of three microprocessors. The
server supports one, two, or four microprocessors only.
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System x3750 M4 Types 8722 and 8733: Installation and Service Guide