Use-Cases: In operation not 24/7. Powered on just on-demand, after each use session powered down. Backing up user data, user photographs, Time Machine backups in sparse bundles, occasional file exchange, occasional DLNA-streaming, smartphone internal flash backups.
Durability, zero-noice and performance wanted.
Considering to have all-ssd NAS with 4x2TB ssd’s - no HDD. Overall physical build volume comparable with commercial 2-bay solutions, eventually bit more if each ssd will need own heatsink. 2.5GB local network, later on eventually 5GB.
yeah, the WD Black SN850X SSD would work great for a household NAS setup. It’s fast, reliable, and quiet, which sounds perfect for your use-case. Plus, going all-SSD with 2TB drives will give you some serious performance. Just make sure you have good airflow or heatsinks for the drives to keep them cool. And with a 2.5 or 5GB network, you’ll be flying!