Mirroring mode installation order
Mirroring mode provides full memory redundancy while reducing the total system memory capacity in half. Memory channels are grouped in pairs with each channel receiving the same data. If a failure occurs, the memory controller switches from the DIMMs on the primary channel to the DIMMs on the backup channel. The DIMM installation order for memory mirroring varies based on the number of processors and DIMMs installed in the server.
Mirroring mode installation rules
In mirroring mode, each memory module in a pair must be identical in size and architecture. The channels are grouped in pairs with each channel receiving the same data. One channel is used as a backup of the other, which provides redundancy.
All memory modules to be installed must be of the same Lenovo part number.
Mirroring can be configured across channels in the same iMC, and the total TruDDR5 memory size of the primary and secondary channels must be the same.
Partial Memory Mirroring is a sub-function of memory mirroring. It requires to follow the memory installation order for memory mirroring.
Mirroring mode with one processor
The following table shows the DIMM installation order for mirroring mode when only one processor (processor 1) is installed.
DIMM configurations that support Software Guard Extensions (SGX). See Enable Software Guard Extensions (SGX) to enable this feature.
| Configuration | DIMM slots | ||||||||||||||||
| 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | ||
| 8 DIMMs | 16 | 14 | 12 | 10 | 7 | 5 | 3 | 1 | |||||||||
| 16 DIMMs | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | |
Mirroring mode with two processors
The following table shows the DIMM installation order for mirroring mode when two processors (processor 1 and processor 2) are installed.
DIMM configurations that support Software Guard Extensions (SGX). See Enable Software Guard Extensions (SGX) to enable this feature.
| Configuration | DIMM slots | ||||||||||||||||
| 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | ||
| 16 DIMMs | 16 | 14 | 12 | 10 | 7 | 5 | 3 | 1 | |||||||||
| 32 DIMMs | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | |
| Configuration | DIMM slots | ||||||||||||||||
| 32 | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | ||
| 16 DIMMs | 32 | 30 | 28 | 26 | 23 | 21 | 19 | 17 | |||||||||
| 32 DIMMs | 32 | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | |