Synology ecosystem match
DS225+ + 2 × 8TB Plus Series
A checked starting combination targeting about 8TB usable with shr / raid 1-style single-drive redundancy.
Lowest checked total$1,204.97Amazon + B&H
Lowest one-store total$1,204.97B&H
Approx. usable8TB
Checked value$150.62/TB
What the bundle contains
Capacity and redundancy
The mirror can continue after one drive fails; RAID is not a backup.
Approximation: $(2 - 1) × 8TB = 8TB$. Filesystem formatting, system partitions, snapshots, and RAID implementation reduce displayed free space.