Active Memory; Memory Scrubbing And Memory Protexion; Memory Mirroring; Hot-Swap Memory - IBM eServer xSeries 455 Type 8855 Hardware Maintenance Manual And Troubleshooting Manual

Active Memory

Active Memory is an IBM feature that improves the reliability of memory through
hot-swap memory, memory mirroring, memory scrubbing, and the Memory
ProteXion feature.

Memory scrubbing and Memory ProteXion

Memory scrubbing tests the memory at regular intervals to detect and report
recoverable memory ECC errors before they can cause server outages.
If the recoverable ECC error rate exceeds the system-defined threshold, the
Memory ProteXion feature replaces the failing bit positions, maintaining reliable
operation. If the recoverable ECC error rate exceeds the threshold again, light path
diagnostics LEDs are lit to indicate the failing DIMM.
You do not have to enable memory mirroring to use memory scrubbing and the
Memory ProteXion feature.

Memory mirroring

Memory mirroring stores data in memory port 1 and memory port 2 simultaneously.
To support memory mirroring, you must install identical dual inline memory modules
(DIMMs) in memory port 1 and memory port 2. For more information, see the
section about installing memory modules in the Option Installation Guide on the IBM
xSeries Documentation CD.
To enable memory mirroring through the Configuration/Setup Utility program, select
Advanced Setup from the main menu, and select Memory Configuration. For
more information about using the Configuration/Setup Utility program, see
Chapter 2, "Configuring the server," on page 11.

Hot-swap memory

You can replace a failed DIMM while the server is turned on, provided that you
have enabled memory mirroring and that you have installed all DIMMs in the
sequence to support memory mirroring.
If a problem with a DIMM is detected, light path diagnostics LEDs are lit to indicate
the failing DIMM. When this occurs, identify the defective DIMM, and then remove
and replace the DIMM. For more information, see the information about installing
memory modules in the Option Installation Guide on the IBM xSeries
Documentation CD.
Chapter 1. General information
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