Synology ecosystem match
DS925+ + 4 × 12TB Plus Series
A checked starting combination targeting about 36TB usable with shr / raid 5-style single-drive redundancy.
Lowest checked total$2,639.95B&H + Newegg
Lowest one-store total$2,759.95B&H
Approx. usable36TB
Checked value$73.33/TB
What the bundle contains
Capacity and redundancy
The array can continue after one drive fails; RAID is not a backup.
Approximation: $(4 - 1) × 12TB = 36TB$. Filesystem formatting, system partitions, snapshots, and RAID implementation reduce displayed free space.