Software Tuning, Performance Optimization & Platform Monitoring
Discussion regarding monitoring and software tuning methodologies, Performance Monitoring Unit (PMU) of Intel microprocessors, and platform updating.

Recommended Memory Layout with nvdimms in play

Hi guys, I have a single nvdimm (Micron 16GB DDR4) that I want to use to speed up an ZFS filer (as slog). Since ZFS loves memory I am wondering how to get to maximum available memory/bandwith while keeping the NVDimm in play. I am running some tests on a S2600STB with a single 6150. From my limited understanding this leads to a few questions/scenarios that I have been trying to answer but without conclusion at this point. If any of you experts could enlighten me/point me to further documentation I'd be most grateful; Assumption NVDimm requires OS Support/driver - the Bios will see it as regular memory module (probably knowing its an nvdimm o/c) and will treat it accordingly Case 1: If an OS without proper support is loaded the nvdimm will just act as regular memory and will be part of the regular interleaving process - thus a 5+1 configuration is best to reach 6 modules and balanced memory configuration (basically its not used as nvdimm so normal rules apply) Case 2: If an OS with nvdimm support/driver is loaded than at some point the nvdimm gets taken out of the regular memory setup (and treated as storage device). The question in this is case is now how the assignment of the memory channels changes - is that being re-evaluated or not? If not - then still a 5+1 config would be best If yes then a 6+1 config might be more beneficial since then the hex channel config would be applicable again I've been trying to simply look it up with deploying different configs, and also simply measuring bandwidth, but that didnt work out as expected (quite bad bw on hex channel and no idea why) Are there maybe Bios settings that govern this? Thanks a lot for any feedback, regards, Thomas
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