Memory Mirroring; Online-Spare Memory - IBM System x3620 M3 7376 Installation And User Manual

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 90. 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
v The maximum available memory is reduced to half of the installed memory when
v Channel 2 DIMM connectors 8 ,7, 15, and 16 are not used in memory-mirroring
The following table lists the installation sequence for installing DIMMs in
memory-mirroring mode.

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 90). 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
v When you enable the memory online-spare feature, you must install three DIMMs
Table 7. Connectors on each memory channel (continued)
Memory channel
Channel 1
Channel 2
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.
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.
mode.
Table 8. Memory-mirroring mode DIMM population sequence
DIMMs
First pair of DIMMs
Second pair of DIMMs
Fourth pair of DIMMs
Fifth pair of DIMMs
Note: DIMM connectors 7, 8, 15, and 16 are not used in memory-mirroring mode.
™
Xeon 5600 series microprocessor.
per microprocessor at a time. The first DIMM must be in channel 0, the second
DIMM in channel 1, and the third DIMM in channel 2. The DIMMs must be
identical in size, type, rank, and organization, but not in speed. The channels run
at the speed of the slowest DIMM in any of the channels.
DIMM connectors
5, 6, 13, 14
7, 8, 15, 16
Number of installed
microprocessors
1
1
2
2
Chapter 2. Installing optional devices
DIMM connector
3, 6
2, 5
14, 11
13, 10
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