# USB Drive Enclosures & Docks — Linux Compatibility Guide

## Chipset Rankings for Linux

| Chipset | UASP | SMART Passthrough | Reliability | Verdict |
|---------|:----:|:-----------------:|:-----------:|:--------|
| **ASMedia ASM1153E / ASM235CM** | ✅ Excellent | ✅ `-d sat` | ✅ Rock-solid | **Gold standard** |
| **ASMedia ASM1351** | ✅ Good | ✅ `-d sat` | ✅ Good | Found in TerraMaster, QNAP enclosures |
| **JMicron JMS578 / JMS561** | ⚠️ Good | ✅ `-d sat,12` | ⚠️ Occasional UAS abort storms | Acceptable with quirks |
| **Realtek RTL9210B-CG** | ⚠️ Mixed | ❌ Poor for SATA | ⚠️ Intermittent disconnects | **Avoid for HDDs** |
| **VIA VL812 / VL822** | ⚠️ Fair | ❌ Often fails | ⚠️ Inconsistent | Not recommended |

### Key insight
**ASMedia is the only chipset that "just works"** on modern Linux kernels with full UASP + SMART passthrough. JMicron works but can produce the same `uas_eh_abort_handler` errors seen with failing USB drives — making it hard to distinguish a bad chipset from a bad drive. Realtek's SATA mode is unreliable.

## Recommended Models

### Single-bay (for one IronWolf Pro / single backup drive)

| Model | Chipset | Price | Notes |
|-------|---------|-------|-------|
| **Sabrent DS-UB3C1** (dock) | ASMedia ASM1153E | ~$18 | Most popular dock on Linux |
| **Sabrent EC-UASP** (enclosure) | ASMedia ASM1153E | ~$20 | Well-tested enclosure |
| **UGREEN CM121** (enclosure) | ASMedia ASM235CM | ~$24 | Newer chip, runs cool |
| **Startech SATDOCKU3SEF** (dock) | ASMedia ASM1153E | ~$32 | Heavy-duty build |

### Two-bay (JBOD — drives appear as separate devices)

| Model | Chipset | Price | Notes |
|-------|---------|-------|-------|
| **TerraMaster D2-320** | ASMedia ASM235CM + JMB575 | ~$75 | **Best choice** — full UASP + SMART, hardware JBOD dip switch, no kernel quirks |
| **Yottamaster D35-2C** | Realtek RTL9210B-CG | ~$65 | Cheaper, but Realtek bridge can have AMD XHCI disconnect issues |
| **Sabrent DS-2BCR** | ASMedia ASM225CM | ~$100 | Premium build, tool-free trays, silent fan |
| **Mediasonic ProBox HF2-SU3S2** | JMS539 (BOT only, no UASP!) | ~$60 | **Avoid** — no UASP, unreliable SMART |
| **ORICO 2-bay** | VIA VL812 lottery | ~$45 | **Avoid** — chipset lottery, underpowered 24W PSU |

## Power Supply Notes

- **Two 3.5" HDDs peak at ~25W each during spin-up** (12V × ~2A)
- Minimum safe PSU for 2-bay: **12V/3A (36W)** — adequate but marginal
- Recommended: **12V/5A (60W)** brick (~$15 upgrade) for headroom
- ORICO's 12V/2A (24W) PSU is dangerously underpowered for two HDDs

## SMART Verification

After connecting, verify everything works:

```bash
# Confirm UASP driver loaded
lsusb -t | grep uas

# Full SMART data
sudo smartctl -a -d sat /dev/sdX

# Check temperature and power-on hours
sudo smartctl -a -d sat /dev/sdX | grep -E 'Temperature|Power_On_Hours'
```

If `smartctl` returns no data or errors, the enclosure chipset doesn't support SMART passthrough.

## JBOD Mode vs RAID

- **JBOD** (Just a Bunch Of Disks) = each drive appears as a separate `/dev/sdX` — what you want for "backup + backup of backup"
- **RAID 0** = striping (fast, no redundancy)
- **RAID 1** = mirroring (redundant but both drives show as one device — NOT what you want for independent backups)
- **RAID mode on the enclosure does NOT replace software backup** — use it in JBOD mode and let rsync/rclone handle the actual backup logic
