IBM X3850 X6, Инструкция по установке и обслуживанию

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Memory rank sparing
This information provides an overview for memory rank sparing.
The server supports memory rank sparing. Memory rank sparing reserves memory
capacity for failover in the event of a DIMM failure, and the reserved capacity is
subtracted from the total available memory. Memory sparing provides less
redundancy than memory mirroring does. If a predetermined threshold of
correctable errors is reached, the contents of the failing DIMM are copied to the
spare memory, and the failing DIMM or rank is disabled.
To enable memory sparing through the Setup utility, select
System Settings →
Memory → Memory Mode
. For more information and notes about installing
DIMMs, see “Installing a memory module” on page 47. For more information and
the DIMM population sequence for memory rank sparing, see “Memory rank
sparing in independent mode” on page 58 and “Memory rank sparing in lockstep
mode” on page 62.
Memory-sparing is supported in both independent memory mode and lockstep
memory mode.
The DIMM installation order for memory rank sparing follows the independent
mode (performance) or lockstep mode (RAS) installation order based on the mode
of operation selected. For more information, see “Independent memory mode” on
page 55, and “Lockstep memory mode” on page 59.
When you use the memory rank sparing feature, consider the following
information:
v
Memory rank sparing is not supported if memory mirroring is enabled.
v
The spare rank must have identical or larger memory capacity than all the other
ranks on the same DDR3 channel.
v
When single-rank DIMMs (that is, 4 GB and 8 GB) are used, a minimum of two
rank DIMMs must be installed per memory channel to support memory sparing.
v When multi-rank DIMMs (that is, 16 GB, 32 GB, and 64 GB) are used, one
multi-rank DIMM can be installed per memory channel to support memory
sparing.
v
The total memory available in the system is reduced by the amount of memory
allocated for the spare ranks.
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System x3850 X6 and x3950 X6 Types 3837 and 3839: Installation and Service Guide