NEC express5800 A2010b User Manual page 199

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Table of Contents

Chapter 2 Preparations

Lock Step + Rank Sparing

In Lock Step + Rank Sparing mode, spare ranks are added to Lock Step mode. If the indication of failure is

detected in running rank, replace the data in unit of Lock Step PAIR by copying it onto spare rank on the same

channel to continue processing.

RAS feature is higher than Lock Step mode, however, the memory capacity available for OS is reduced by the

capacity of spare rank from the installed memory.

Memory Riser #1

(spare rank)

Occurrence of Rank Sparing error (When the same DIMMs are used for failing rank and spare rank)

Memory Riser #1

running system

Combinations of channels 0 and 1, and 2 and 3 are used for Lock Step+RankSparing

Use NE3302-H020F/H021F/H022F/H023F additional memory for Lock

Step+RankSparing mode.

Use the DIMMs of same model for Lock Step PAIR.

Memory Buffer #1

Memory Controller #1

Failure occurrence

Memory Buffer #1

Memory Controller #1

Express5800/A1040b, A2040b, A2020b, A2010b User's Guide

1. Installing / Removing Internal Options

Memory Buffer #2

Memory Buffer #2

(spare rank)

Memory Controller #2

(spare rank)

Memory Controller #2

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