– Memory-mirroring mode replicates and stores data on two pairs of DIMMs
simultaneously. If a failure occurs, the memory controller switches from the
primary pair of memory DIMMs to the backup pair of DIMMs. To enable
memory mirroring through the Setup utility, select System Settings →
Memory. For more information, see “Using the Setup utility” on page 132.
– DIMMs must be installed in sets of four. The DIMMs in each set must be the
same size and type. This is applicable also when an optional memory tray is
installed in the server and an optional IBM MAX5 for System x memory
expansion module attached to the server. You must install DIMMs in sets of
four DIMMs for memory-mirroring mode in each (server, memory tray, and
the MAX5).
– 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.
– The following table lists the DIMM installation sequence for
memory-mirroring mode when one or two microprocessors and no memory
tray is installed in the server:
Table 9. Memory-mirroring mode DIMM population sequence when one or two
microprocessors and no memory tray is installed
Sets of DIMMs
Number of installed
microprocessors
DIMM connector
population sequence with
no memory tray
Set1 1or2 1,8,9,16
Set 2 1 or 2 3, 6, 11, 14
Set 3 1 or 2 2, 7, 10, 15
Set 4 1 or 2 4, 5, 12, 13
– The following table lists the DIMM installation sequence for
memory-mirroring mode when two microprocessors and a memory tray is
installed in the server:
Table 10. Memory-mirroring mode DIMM population sequence when two microprocessors
and a memory tray is installed
Sets of DIMMs
Number of installed
microprocessors
DIMM connector
population sequence
on the system board
DIMM connector
population sequence
on the memory tray
Set 1 2 1, 8, 9, 16 17, 24, 25, 32
Set 2 2 3, 6, 11, 14 19, 22, 27, 30
Set 3 2 2, 7, 10, 15 18, 23, 26, 31
Set 4 2 4, 5, 12, 13 20, 21, 28, 29
v 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.
The following illustration shows the location of the DIMMs connectors on the
system board.
Chapter 2. Installing optional devices 55
To Next Page
Loading...
