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Rank sparing mode

In rank sparing mode, one rank of a memory module works as the spare rank for the other ranks on the same channel. The spare rank is not available as system memory.

Note

  • All memory modules to be installed must be the same type with the same capacity, frequency, voltage, and ranks.

  • All Performance+ DIMMs in the server must be of the same type, rank, and capacity (the same Lenovo part number) to operate at 2933 MHz in the configurations with two DIMMs per channel. Performance+ DIMMs cannot be mixed with other DIMMs.

  • If the rank of installed memory modules is one rank, follow the installation rules listed in the following tables. If the rank of installed memory modules is more than one rank, follow the installation rules of independent mode.

The following table shows the memory module population sequence for rank sparing mode when only one processor (Processor 1) is installed.

Table 1. Rank sparing mode with one processor
TotalProcessor 1Total
DIMMs121110987 654321DIMMs
2 652
4    87 65    4
687 65436
8  10987 6543  8
1010987 65432110
12121110987 65432112

The following table shows the memory module population sequence for rank sparing mode when two processors (Processor 1 and Processor 2) are installed.

Table 2. Rank sparing mode with two processors
TotalProcessor 2Processor 1Total
DIMMs242322212019 181716151413121110987 654321DIMMs
4 1817 654
6       1817        87 65    6
82019 181787 658
10    2019 1817        87 6543  10
122019 1817161587 654312
14    2019 18171615    10987 6543  14
1622212019 1817161510987 654316
18  22212019 18171615    10987 65432118
2022212019 18171615141310987 65432120
22  22212019 181716151413121110987 65432122
24242322212019 181716151413121110987 65432124