Adding And Replacing A Memory Card - IBM 71412RU User Manual

v Memory scrubbing is an automatic daily test of all the system memory that
v Memory ProteXion reassigns memory bits to new locations within memory when

Adding and replacing a memory card

At least one memory card with one pair of DIMMs must be installed for the server
to operate correctly.
Adding a memory card
To add a memory card, complete the following steps:
1. Read the safety information that begins on page v and "Installation guidelines"
2. Turn off the server and peripheral devices, and disconnect the power cords and
3. Remove the server cover (see "Removing the cover and bezel" on page 30).
4. Prepare the memory card:
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IBM System x3850 M2 and System x3950 M2 Types 7141 and 7233: User's Guide
e. Select Memory Mirroring Settings.
f. Enable the memory mirroring setting from within this window.
g. Save the settings 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 stored in the memory port 1 DIMMs, and a second
copy is stored in the memory port 2 DIMMs. During a read operation, the data is
read from the DIMM with the fewest reported memory errors through memory
scrubbing.
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.
detects and reports memory errors that might be developing before they cause a
server outage.
Note: Memory scrubbing and Memory ProteXion technology work with each
other and do not require that memory mirroring be enabled.
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 event is
logged for informational purposes. Provided that there are enough good locations
to enable the correct operation of the server, no further action is taken other than
recording the event 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.
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.
on page 28.
all external cables as necessary to replace the device.
a. Touch the static-protective package that contains the memory card to any
unpainted surface on the outside of the server; then, remove the memory
card from the package.
b. Place the memory card on a flat, static-protective surface, with the DIMM
connectors facing up.