Memory Mirroring - NEC Express5800/R120b-1 User Manual

9-34 Upgrading Your Server

Memory mirroring

The memory mirroring feature writes the same data into two groups of DIMMs corresponding with
each other between memory channels (channels 0 and 1) to provide data redundancy.
IMPORTANT:
The memory mirroring feature uses channels 0 and 1. In memory mirroring
configuration, the memory channel 2 of each CPU (CPU1-DIMM3/6,
CPU2-DIMM3/6) is disabled.
To use the Memory Mirroring feature, an additional memory stick
(N8102-387/388/389/390/391) is required.
Example:
In 2-CPU
configuration
CH0
Data 1
Data 2
Data 3
Data 4
NOTE:
physical capacity.
CH0
CPU1-DIMM4
Mirror set
#3
CPU1-DIMM1
Mirror set
#1
CH1
Data 1
Data 2
Data 3
Data 4
CH0
CPU2-DIMM4
Mirror set
#4
CPU2-DIMM1
Mirror set
#2
The operating system only recognizes a half of the total
CPU1
Memory controller
CH1
CPU1-DIMM6
CPU1-DIMM5
CPU1-DIMM2
CPU1-DIMM3
CPU2
Memory controller
CH1
CPU2-DIMM6
CPU2-DIMM5
CPU2-DIMM3
CPU2-DIMM2
CH2
CH2