Updated August 26, 2026.
The TerraMaster D9-320 is a nine-bay USB DAS for expanding a computer, server, or compatible NAS. It provides high capacity and per-drive power controls, but all nine devices share one 10Gbps USB link and must be unmounted correctly.
A DAS is not a NAS
The D9-320 has no server, network interface, or operating system. It exposes disks to a host over USB. Sharing, RAID, permissions, and backup come from Windows, macOS, Linux, TOS, Unraid, TrueNAS, or Proxmox.
Connecting it to a NAS does not guarantee that the NAS can create pools or RAID on USB disks. Check the vendor matrix before building critical storage on an unsupported feature.
Nine drives behind 10Gbps USB
USB 3.2 Gen 2 provides 10 Gbps theoretical bandwidth for the enclosure. Multiple SSDs can saturate it; HDD deployments emphasize capacity. Results near 1,000 MB/s require suitable drives and workloads and are not available per bay simultaneously.
Use the supplied cable and a direct port rather than a hub. USB4 or Thunderbolt hosts may connect, but the D9-320 still operates at its own interface limit.
Per-drive power control
Per-bay switches can shut down idle drives only after they are unmounted and all writes, cache activity, RAID jobs, scrubs, and virtual machines have stopped. Cutting power to a mounted disk can corrupt its file system.
Master power and restart behavior can help unattended servers, but test them with the host and a UPS. They do not make the enclosure a UPS.
RAID, JBOD, and individual disks
The enclosure exposes individual drives. RAID, where used, is created by host software or a compatible TerraMaster NAS. That is flexible, but moving the set may require the same storage technology.
With nine disks, consider two-drive fault tolerance and rebuild duration. A DAS RAID still requires a separate backup.
Cooling, noise, and power
Nine HDDs produce heat, vibration, and spin-up current. Allow ventilation, use approved drives, monitor temperature, and avoid enclosed cabinets. Power switches save energy only when the workflow permits unmounting drives.
Drive choice contributes more noise than the chassis. High-speed enterprise disks can be clearly audible in a studio.
Use cases and security
It suits video archives, local backups, Unraid, and servers that lack drive ports, provided USB is managed reliably. It is a poor choice for frequently disconnected RAID or as the only copy.
Encrypt volumes through the host and document which bay maps to each disk. Label drives physically before creating a pool.
Verdict
The D9-320 is a compact way to attach substantial capacity, but it requires a clear understanding of USB, unmounting, and software RAID. It is expansion—not an automatic NAS or backup strategy.