Intel® Server Board SE7520JR2

Functional Architecture

3.3.6.6Memory Mirroring

The memory mirroring feature is fundamentally a way for hardware to maintain two copies of all data in the memory subsystem, such that a hardware failure or uncorrectable error is no longer fatal to the system. When an uncorrectable error is encountered during normal operation, hardware simply retrieves the “mirror” copy of the corrupted data, and no system failure will occur unless both primary and mirror copies of the same data are corrupt simultaneously. Mirroring is supported on dual-channel DIMM populations symmetric both across channels and within each channel. As a result, on the Server Board SE7520JR2 there are two supported configurations for memory mirroring:

•Four DIMM population of completely identical devices (two per channel). Refer to Figure 6, DIMMs labeled 1A, 2A, 1B and 2B must all be identical.

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Figure 6. Four DIMM Memory Mirror Configuration

•Six DIMM population with identical devices in slot pairs 1 and 2/3 on each channel. DIMM slots labeled 1A, 1B must be populated with identical dual ranked DIMMs, while DIMMs in the remaining slots must be identical single rank DIMMs. DIMMs between the two groups do not have to be identical. This configuration is only valid with DDR2 memory.

DDR266/333 mirrored memory configurations are only capable of supporting 2 DIMMs per channel.

Revision 1.0

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C78844-002