Using The Memory Ras Features - NEC Express5800/R120b-2 User Manual

Using the Memory RAS Features

The server has RAS feature including "Standard memory configuration (x4 SDDC ECC memory)",
a "memory mirroring feature", a "memory sparing feature", and a "LockStep (x8 SDDC ECC
memory) feature". SDDC (Single Device Data Correction) allows automatic correction of memory
error (multi-bit error).
IMPORTANT:
To use the memory mirroring feature or LockStep (x8 SDDC ECC
memory) feature, an additional memory stick
(N8102-387/388/389/390/391) is required.
To use x4 SDDC ECC memory feature, an additional memory stick
(N8102-371/372/373/374/375) is required.
The memory area on the motherboard of the server is divided into two memory channels as shown
in the figure below.
Memory controller
Memory controller
CH0
CPU1-DIMM5
CPU1-DIMM4
CPU1-DIMM1 CPU1-DIMM2
The memory mirroring and LockStep features keep memory redundancy between memory channels
by monitoring or altering memory active/inactive status, respectively.
CPU1
CH1 CH2
CPU1-DIMM6
CPU1-DIMM3
Upgrading Your Server 9-35
CPU2
Memory controller
Memory controller
CH0
CH1
CPU2-DIMM5
CPU2-DIMM4
CPU2-DIMM2
CPU2-DIMM1
CH2
CPU2-DIMM6
CPU2-DIMM3