User's Guide

1. Installing Internal Optional Devices
Express5800/R120d-1E User’s Guide
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Chapter 2 Preparations
(1)
Memory Mirroring Feature
The memory mirroring feature writes the same data into two groups of DIMMs corresponding with each other
between memory channels (channels 2 and 3) to provide data redundancy.
Important
 The Memory Mirroring feature uses channels 2 and 3. In memory mirroring
configuration, the memory channel 1 of each CPU (CPU1-DIMM1/4,
CPU2-DIMM1/4) is disabled.
 To use the Memory Mirroring feature, additional memory board
(N8102-493/494/495/496), equipped with two DIMMs of same model, is required.
Tips
The operating system only recognizes a half of the total physical capacity.
The memory mirroring feature can be used under the following conditions:
 Install DIMMs in two DIMM sockets configuring a mirror set.
 All the installed DIMMs should have the same capacity.
 Run SETUP (refer to Chapter 2 (1. System BIOS) in "Maintenance Guide"), change parameters
appropriately in the [Mirror] menu selected as shown below, save the settings and exit from SETUP.
[Advanced] – [Memory Configuration] – [Memory RAS Mode] – [Mirror]
Run SETUP again, and check if the status of additionally installed DIMMs shows "Mirror".
 Installation order depends on CPU configuration. See the figure below.
The mirroring cannot be configured in the following case:
 Memory mirroring within a specific memory channel
Notes on Configuring Memory Mirroring
If you install or remove DIMMs that unable to configure memory mirroring, parameter for [Memory RAS Mode]
is changed from "Mirror" to "Independent".