DIMM Fault Remind Circuit and ECC Errors

The following topics describe the components of the Fault Remind circuitry:

• Fault Remind Button and Charge Status Indicator

• DIMM Fault Indicators

Fault Remind Button and Charge Status Indicator

The blue Fault Remind button (SW3001) is located on the motherboard next to the Charge Status indicator (CR3002). The Charge Status indicator indicates the usability of the test circuit. When the Fault Remind button is pressed, the Charge Status indicator, lights green to indicate that there is sufficient voltage present in the Fault Remind circuit to activate the fault indicators. DIMM Fault indicators identify DIMMs in a fault state.

DIMM Fault Indicators

The DIMM Fault indicators are located on the motherboard next to each DIMM slot. The amber indicators light up when the Fault Remind button is pressed and a DIMM fault condition exists.

Related Information:

• About the DIMM and Processor Test Circuit

• Identify Faulty DIMMs

Inconsistencies Between DIMM Fault LEDs and the BIOS Isolation of Faulty DIMMs

When a single DIMM is marked as faulty by Oracle ILOM (for example, fault.memory.intel.dimm.training-failed is listed in the SP event log), BIOS might disable the entire memory channel that contains the faulty DIMM as failing, that is, up to three DIMMs. As a result, the memory available to the operating system is reduced. However, when the Fault Remind button is pressed, only the fault status indicator (LED) associated with the faulty DIMM lights. The fault LED for the other DIMM in the memory channel remains off. Therefore, you can correctly identify the faulty DIMM.

When the faulty DIMM is replaced and the DIMM fault is cleared using Oracle ILOM, the memory available to the operating system returns to normal. You can use the Oracle ILOM web interface or the command-line interface (CLI) to manually clear faults. For information on how to use the Oracle ILOM web interface or the CLI to clear server faults, see the Oracle Integrated Lights Out Manager (ILOM) 3.1 Documentation Library at: http://www.oracle.com/goto/ILOM/docs.

Error Correction and Parity

The server's processor provides data parity protection on its internal cache memories and error-correction code (ECC) protection. The system can detect the following types of errors: correctable and uncorrectable memory ECC errors and uncorrectable CPU internal errors. Errors are recorded in the Oracle ILOM system event log (SEL).

Advanced ECC corrects up to 4 bits in error on nibble boundaries, as long as they are all in the same DRAM. If a DRAM fails, the DDR3 DIMM continues to function. For instructions for clearing DDR3 DIMM faults, refer to http://www.oracle.com/goto/x86AdminDiag/docs.