NVRAM is a separate DIMM from main memory, while NVMEM uses part of the main memory and is not a separate DIMM. The document provides examples of hardware showing NVRAM as a separate 4GB DIMM, while NVMEM on a filer uses 2.4GB of the total 20GB main memory. It clarifies the hardware difference between NVRAM using a separate DIMM and NVMEM utilizing space within main memory.

1. NVRAM vs NVMEM
Hardware difference
NVRAM: is a separate DIMM and not part of the main-memory
For example:
FAS8020: 24GB Per Node | 4 GB NVRAM
If you run this command, you can clearly see all the DIMM listed.
::>controller fru show-manufacturing-info -node NODE-01
FRU Description FRU Serial Number FRU Part Number FRU Rev.
DIMM-1 94-03-1602-xx SGB721xx
DIMM-2 94-03-1602-xx SGB721xx
DIMM-3 94-03-1602-xx SGB721xx
NVRAM9 DIMM 94-02-1552-xx SGB7D1xx
This clearly indicates that there are 3 Main-Memory DIMM each: 8 GB, 8x3=24GB , and there is
separate 4GB DIMM for NVRAM activity.
NVMEM: is NOT a separate DIMM
For example:
7-mode Filer | FAS3250 | 20GB Total – 2.4 GB of NVMEM.
NVMEM: is NOT a separate DIMM, Uses part of the Main Memory. It clearly says it in the sysconfig
output.
>sysconfig -a
Memory Size: 20480 MB
NVMEM Size: 2400 MB of Main Memory Used
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March, 2019