Used the sizing spreadsheet - average row size - with 700 nodes, 20 DCI's per node = 14,000 DCI's, 300 sec polling (CPU per second but file Systems 1 per 15 minute - so averaged) - with a 365 day retention = 124GB. Not everything will have 365 day retention - but - taking my worst possible case.
Based on the following post - I do not appear to be pushing NetXMS so
https://www.netxms.org/forum/general-support/netxms-cpu-usage-high/msg24645/#msg24645
I started with PostgreSQL and unless anyone suggests otherwise, I will go with PostgreSQL - on same server as NetXMS - with 150'ish GB of SAN based SSD storage, a couple of cores and a chunk of mem (plenty of both an a B200 M3).
Suggestions / Feedback welcome.
We have very good experience with PostgreSQL, that's definitely our recommendation. You may also try TimescaleDB - this is PostgreSQL extension optimized for time series data. We have added support for TimescaleDB recently and so far it shows significant performance improvement for large deployments.
Best regards,
Victor