IBM X3850 X6, Инструкция по установке и обслуживанию

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Table 10. DIMM population sequence for independent memory mode (continued)
DIMM installation order
Independent mode with
memory mirroring disabled Independent mode with
memory mirroring enabled
23 DIMM connector 21
24 DIMM connector 18
Memory mirroring
Use this information for an overview of memory mirroring.
Memory-mirroring replicates and stores data on DIMMs across all four memory
channels for the compute book and DDR3 channels simultaneously. If a failure
occurs, the memory controller switches from the DIMMs on the primary channels
to the DIMMs on the backup channels. To enable memory mirroring through the
Setup utility, select
System Settings
→
Memory
→
Memory Mode . For more
information, see “Using the Setup utility” on page 126. For more information and
notes about installing DIMMs, see “Installing a memory module” on page 47. For
more information and the DIMM population sequence for memory mirroring, see
“Memory mirroring in independent memory mode” on page 56 and “Memory
mirroring in lockstep mode” on page 60.
Memory mirroring is supported in independent mode and lockstep mode.
When you use the memory mirroring feature, consider the following information:
v
The server supports single-socket memory mirroring. The compute book
memory channel 0 mirrors memory channel 1, and memory channel 2 mirrors
memory 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 compute book when using the
memory mirroring feature.
v
The DIMM population must be identical (size, organization, etc.) 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.
Chapter 2. Installing optional devices
53