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Memory sparing mode
Sparing is only supported in a
•Copy the contents of a failing FBDIMM rank to a backup or spare FBDIMM rank
•Disable the failing FBDIMM rank
These actions are completed before the FBDIMM rank begins to generate more serious memory ECC uncorrectable errors that would bring down the system by corrupting memory.
Spare memory configurations
Spared memory configurations do not provide redundant copies of memory. In addition, the system cannot continue to operate when an ECC Uncorrectable Error /
The underlying assumption is that FBDIMMs generating increasing numbers of ECC Correctable Errors are eventually prone to ECC Uncorrectable Errors. These FBDIMMs should be removed from service prior to causing a system crash.
Once a FBDIMM rank exceeds the specified frequency of ECC Correctable Errors the contents of the failing FBDIMM rank are copied to the spare (reserved) FBDIMM rank. Hardware then isolates and removes the failing FBDIMM rank from the set of active FBDIMM ranks. These actions prevent future memory errors and maintain system integrity.
Note: The memory sparing feature requires that the spare FBDIMM rank be at least the size of the largest primary FBDIMM rank in use. When sparing is enabled, the BIOS selects the spare rank automatically during POST. No manual configuration of this feature is required beyond turning on the feature in BIOS Setup. With sparing enabled, the total effective memory size is reduced by the size of the spare FBDIMM rank(s).
