i went ahead and setup 2x2tb wd red+ as raid1 in shr1 in synology 2bay 223j,but i still have commenters said i should deploy 2x SSD instead, for cache and indexing, i dont quite undetstand what benefits i can get from using SSD vs HDD.

just offload photos from mobile storage to nas every 3 weeks, plus occasionally steam drama series from nas via dlna or plex.

if i remembered correctly, the crucial mx500 had a same price point vs a HDD for 2TB hence i went ahead to purchase SSD use for NAS.