IBM 7383, Инструкция по установке и обслуживанию

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Memory mirrored channel
Memory mirrored channel 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 can enable memory mirrored in the Setup utility (see “Starting the Setup
utility” on page 106).
When you use the memory mirrored channel feature, consider the following
information:
v
When you use memory mirrored channel, you must install a pair of DIMMs at a
time. The two DIMMs in each pair must be identical in size, type, and rank
(single, dual, or quad), and organization, but not in speed. The channels run at
the speed of the slowest DIMM in any of the channels.
v
The maximum available memory is reduced to half of the installed memory
when memory mirrored is enabled. For example, if you install 64 GB of memory
using RDIMMs, only 32 GB of addressable memory is available when you use
memory mirrored channel.
The following diagram lists the DIMM connectors on each memory channel.
Note: You can install DIMMs for microprocessor 2 as soon as you install
microprocessor 2; you do not have to wait until all of the DIMM connectors for
microprocessor 1 are filled.
The following table shows the installation sequence for memory mirrored mode:
Table 35. Memory mirrored channel mode DIMM population sequence
Number of DIMMs
Number of installed
microprocessor
DIMM connector
First pair of DIMMs 1 1, 4
Second pair of DIMMs 1 9, 12
Third pair of DIMMs 1 2, 5
Fourth pair of DIMMs 1 8, 11
Fifth pair of DIMMs 1 7, 10
Figure 62. Connectors on each memory channel
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System x3500 M4 Type 7383: Installation and Service Guide