Non-Mirroring (Independent Mode); Memory Mirroring - IBM System x3750 M4 Type 8722 Installation And Service Manual

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.

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
v DIMMs must be installed in pairs for each microprocessor when using the
v The DIMM population must be identical for memory channel 0 and memory
v Memory mirroring reduces the maximum available memory by half of the
v The following table lists the DIMM installation sequence for memory-mirroring
44
System x3750 M4 Types 8722 and 8733: Installation and Service Guide
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.
Table 8. DIMM population sequence for non-mirroring mode (independent mode)
Number of
installed DIMM connector population
microprocessors sequence on the system board
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
channel 1, and memory channel 2 mirrors channel 3. This mirroring provides
redundancy in memory but reduces the total memory capacity in half.
memory mirroring feature.
channel 1, and identical for memory channel 2 and memory channel 3.
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.
mode.
Note: The server does not support a configuration of three microprocessors. The
server supports one, two, or four microprocessors only.
DIMM connector population
sequence on the microprocessor
and memory expansion tray
25, 37, 36, 48, 28, 40, 33, 45, 26, 38,
35, 47, 29, 41, 32, 44, 27, 39, 34, 46,
30, 42, 31, 43