NEC EXP805 User Manual page 84

Chapter 2 Preparations
(1) Memory Mirroring Function
Memory Mirroring Function is a function to generate redundancy by writing the same data into DIMM
group (mirror set) composed of three channels under the same memory controller (channel1, channel 2
and channel 3 or channel 4, channel 5 and channel 6).
Ex: Configuration with 2 CPUs
Mirror
Set
Mirror
Set
Data 2
Data 1 Data 1
Data 3
Data 2 Data 3
Data 4 Data 4 Data 5
Data 5 Data 6 Data 6
Mirror
Set
Mirror
Set
The followings are the conditions to use this function.
Install 12 DIMMs per CPU.
●
Use DIMMs with the same product number for the device.
●
Change the following parameters and save them.
●
From system utility, set "System Configuration > BIOS/Platform Configuration (RBSU) > Memory
Operations > Advanced Memory Protection" to "Mirrored Memory with Advanced ECC Support".
● After rebooting, confirm that "Advanced Memory Protection Mode：Memory Mirroring with Advanced
ECC" is displayed in POST.
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CPU1 (PROC1)
Memory Controller 1
CPU2 (PROC2)
Memory Controller 1
Tips  When Memory Mirroring Function is effective and "Memory Mirroring Mode" is
set to "Full Mirroring," total 50 % of available memory can be used from the
operating system.
 When Partial Mirroring is used, set the "Memory Mirroring Mode" option. For
details on the options, refer to "1. System Utilities" in Chapter 1 of "Maintenance
Guide (Common)".
Important Single rank DIMMs do not support the Memory Mirroring function.
Express5800/R120h-2M (2nd-Gen) User's Guide
1. Installing Internal Optional Devices
Memory Controller 2
Memory Controller 2
Mirror
Set
Mirror
Set
Mirror
Set
Mirror
Set