User's Guide

9-40 Upgrading Your Server
Memory sparing
Memory sparing is a feature whereby channel 2 of the memory controller in each CPU is designated
as a "spare" channel and the DIMMs (memories) that use that channel are put on standby so that
operations can be automatically switched to a standby DIMM if a correctable error occurs in one of
the DIMMs operating under the control of the memory controller, allowing processing to continue
unimpeded.
IMPORTANT:
 The memory sparing feature is not supported by the
N8100-1644F/1650F.
 Additional memory sticks (N8102-371/372/373/374/375) are
required to use the memory sparing feature.
 The capacity of the additional memory sticks must match the
capacity of the other memory sticks used in the server.
Example: Memory sparing in a 2-CPU configuration
Memory controller
Memory controller
CPU1
CPU2
CH0
CH1
CH2
CH0
CH1
CH2
Spare set #3
Spare set #1
Spare set #4
Spare set #2
CPU1-DIMM 4 CPU1-DIMM 5 CPU1-DIMM 6
CPU1-DIMM 1 CPU1-DIMM 2 CPU1-DIMM 3
CPU2-DIMM 4 CPU2-DIMM 5 CPU2-DIMM 6
CPU2-DIMM 1 CPU2-DIMM 2 CPU2-DIMM 3
Operating
On standby (spare)
Operating On standby (spare)
NOTE: The capacity of the DIMMs recognized by the operating
system is less than the DIMMs' physical capacity. The capacity
recognized by the operating system depends on the number of memory
sticks inserted and the capacity of each stick.