Fujitsu PRIMERGY RX800 S2 Operating Manual page 121

Hot-plug Components
Ê Enable the memory mirroring setting from within this window.
Ê Save and exit the Configuration/Setup Utility program.
When memory mirroring is enabled, the data that is written to memory is stored
in two locations. One copy is kept in the memory port 1 DIMMs, while a second
copy is kept in the memory port 2 DIMMs. During the execution of the read
command, the data is read from the DIMM with the least number of reported
memory errors through memory scrubbing, which is enabled with memory
mirroring.
If memory scrubbing determines that a DIMM is damaged beyond use, read and
write operations are redirected to the remaining good DIMMs. Memory
scrubbing then reports the damaged DIMM and light path diagnostics displays
the error. After the damaged DIMM is replaced, memory mirroring then copies
the mirrored data back into the new DIMM.
Memory scrubbing and Memory ProteXion
I
Memory scrubbing and Memory ProteXion technology work with each
other and do not require memory mirroring to be enabled to work.
Memory scrubbing is an automatic daily test of all the system memory that
detects and reports memory errors that might be developing before they cause
a server outage.
When an error is detected, memory scrubbing determines whether the error is
recoverable. If it is recoverable, Memory ProteXion is enabled and the data that
was stored in the damaged locations is rewritten to a new location. The error is
then reported so that preventive maintenance can be performed. Provided that
there are enough good locations to enable the correct operation of the server,
no further action is taken other than recording the error in the error logs.
If the error is not recoverable, memory scrubbing sends an error message to
light path diagnostics, which lights LEDs to guide you to the damaged DIMM. If
memory mirroring is enabled, the mirrored copy of the data in the mirrored
DIMM is used to refresh the new DIMM after it is installed.
Memory ProteXion reassigns memory bits to new locations within memory
when recoverable errors have been detected. When a recoverable error is found
by memory scrubbing, the Memory ProteXion feature writes the data that was
to be stored in the damaged memory locations to spare memory locations within
the same DIMM.
U41621-J-Z156-1-76
Memory Cards
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