IBM x3630 M3 7377, Problem Determination And Service Manual

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The following table lists the DIMM connectors on each memory channel.
Table 12. Connectors on each memory channel
Memory channel DIMM connectors
Channel 0 2, 3, 10, 11
Channel 1 5, 6, 13, 14
Channel 2 7, 8, 15, 16
Memory mirroring
Memory-mirroring mode replicates and stores data on two pairs of DIMMs within
two channels simultaneously. If a failure occurs, the memory controller switches
from the primary pair of memory DIMMs to the backup pair of DIMMs. You must
enable memory mirroring through the Setup utility. For details about enabling
memory mirroring, see “Using the Setup utility” on page 235. When you use the
memory mirroring feature, consider the following information:
v To support memory mirroring, the DIMMs in each pair must match but the pairs
can be different from each other. For example, the first pair of DIMMs must
match and the second pair of DIMMs must match; however, the DIMM type for
the first and second pair of DIMMs can be different from each other.
v
The maximum available memory is reduced to half of the installed memory when
memory mirroring is enabled. For example, if you install 64 GB of memory, only
32 GB of addressable memory is available when you use memory mirroring.
v
Channel 2 DIMM connectors 8 ,7, 15, and 16 are not used in memory-mirroring
mode.
The following table lists the installation sequence for installing DIMMs in
memory-mirroring mode.
Table 13. Memory-mirroring mode DIMM population sequence
DIMMs
Number of installed
microprocessors
DIMM connector
First pair of DIMMs 1 3, 6
Second pair of DIMMs 1 2, 5
Fourth pair of DIMMs 2 14, 11
Fifth pair of DIMMs 2 13, 10
Note: DIMM connectors 7, 8, 15, and 16 are not used in memory-mirroring mode.
When you install or remove DIMMs, the server configuration information changes.
When you restart the server, the system displays a message that indicates that the
memory configuration has changed.
Online-spare memory
The memory online-spare feature disables the failed memory from the system
configuration and activates an online-spare DIMM to replace the failed active DIMM.
You can enable either online-spare memory or memory mirroring in the Setup utility
(see “Using the Setup utility” on page 235). When you use the memory online-spare
feature, consider the following information:
v
The memory online-spare feature is supported on server models with an Intel
Xeon
™
5600 series microprocessor.
v
When you enable the memory online-spare feature, you must install three DIMMs
per microprocessor at a time. The first DIMM must be in channel 0, the second
Chapter 5. Removing and replacing server components
165