Setup:
- Host: Beelink SER5 Max (AMD Ryzen 5 5560U, running Proxmox)
- Storage: TerraMaster D4-320 (4-bay, USB 3.2 Gen2, ASMedia 174c:235c controller)
- Connected via powered Anker USB hub (with PD charger) to the Beelink
- Single ZFS pool (
tank) serving Plex, qBittorrent, and Proxmox VM backups via an LXC container - The pool drops from time to time, usually during heavy load (e.g. 4K streaming via Plex)
The problem
The D4-320 silently disconnects from the USB bus — no kernel reset messages, the block device just vanishes. ZFS loses the pool and everything dependent on it freezes (Plex stops mid-stream, qBittorrent shows missing files, backups fail). Adding a powered hub helped significantly but didn't eliminate the issue.
Evidence
1. USB protocol error at boot (error -71 = EPROTO) — happens on every boot:
$ journalctl -k -b | grep "usb 4-2"
May 02 00:44:48 proxmox kernel: usb 4-2: Device not responding to setup address.
May 02 00:44:48 proxmox kernel: usb 4-2: Device not responding to setup address.
May 02 00:44:48 proxmox kernel: usb 4-2: device not accepting address 2, error -71
2. ZFS pool re-imported ~20 times in 3 weeks — each import means a reboot or USB drop:
$ zpool history tank | grep import | tail -8
2026-04-19.02:00:20 zpool import -c /etc/zfs/zpool.cache -N tank
2026-04-24.23:03:15 zpool import -c /etc/zfs/zpool.cache -N tank
2026-04-26.02:08:26 zpool import -c /etc/zfs/zpool.cache -N tank
2026-04-29.23:35:17 zpool import -c /etc/zfs/zpool.cache -N tank
2026-05-01.23:09:47 zpool import -c /etc/zfs/zpool.cache -N tank
2026-05-02.00:44:58 zpool import -c /etc/zfs/zpool.cache -N tank
3. 12-minute silent outage with no dmesg warnings — watchdog log:
[00:32:31] Block device missing — attempting USB rebind [00:34:38] Block device missing — attempting USB rebind [00:38:50] Block device missing — attempting USB rebind [00:43:05] Block device missing — attempting USB rebind [00:45:15] Pool healthy (ONLINE) — mounts refreshed
text
What I've already tried
usbcore.autosuspend=-1in GRUB- ZFS cachefile persistent auto-import on boot
- Backup bandwidth throttled to 100 MB/s (prevents backup-triggered drops)
- Watchdog script running every 2 minutes to auto-recover pool + restart LXC
- Tried UAS — caused constant
reset SuperSpeed Plusstorms, reverted to BOT (usb-storage) - Powered Anker USB hub with PD charger between Beelink and D4-320 — helped a lot but disconnects still occur
- Drive temperature is healthy (30°C, max recorded 35°C)
My plan
I don't want to buy a different DAS or PCIe card. Instead I'm considering buying a Raspberry Pi 5 and using it as a dedicated NAS — D4-320 connected to the Pi via USB, Pi serves storage over NFS to the Beelink. The Beelink keeps running Proxmox + VMs but accesses storage over the network instead of directly.
I heard that Raspberry Pi 5 has a stable USB controller and I hope to fix my problem with that.
Questions
Does RPi5 + D4-320 as a dedicated NAS make sense, or will I hit the same USB instability
Any other ideas for stabilising D4-320 on USB that I haven't tried yet?
Does it even make sense to try with RPi5? Or will I waste another 200USD on hardware for that?