Greetings.
It appear memory mirroring is your memory HA type option
https://www.cisco.com/c/dam/en/us/products/collateral/servers-unified-computing/ucs-c-series-rack-servers/memory-guide-c220-c240-b200-m5.pdf
This basically reduces available memory to 50%, but all primary DIMMs are mirrored...
NOTE: When memory mirroring is enabled, the memory subsystem simultaneously
writes identical data to two DIMMs. If a memory read from primary DIMM returns
incorrect data due to an uncorrectable memory error, the system automatically
retrieves the data from the secondary DIMM in the mirrored pair. Thus, an error in
one DIMM does not affect the mirrored data, and operation continues unless the
error propagates to both the DIMMs in the mirrored pair. Memory mirroring reduces
the amount of memory available to the operating system by 50% because only one of
the two DIMMs in the mirrored pair provides data.
Thanks,
Kirk...
