External Storage for Home Servers Guide

Q: Should I format as ext4 or exFAT?

- **ext4:** Best for Linux-only servers. Journaled, permissions support, reliable. - **exFAT:** Best if the drive needs to work with Windows and Mac too. No journaling, no permissions. - **NTFS:** Works on Linux via ntfs-3g but slower. Use if the drive is primarily Windows.

Quick Recommendation

External storage is for backups, not your primary NAS. USB-attached drives are fine as backup destinations (3-2-1 rule), expansion storage, or cold archives. For primary storage serving files to your network, use internal drives connected via SATA or an HBA card — USB adds latency, lacks SMART monitoring reliability, and can disconnect under load.

If you need external multi-bay storage, get a DAS (Direct Attached Storage) enclosure with USB 3.2 Gen 2 (10 Gbps) or Thunderbolt. Avoid USB 2.0 anything — it’s too slow for multi-terabyte drives.

When External Storage Makes Sense

Use Case	External Storage Good?	Why
3-2-1 backup destination	Yes	Offline/offsite backup drive
Cold archive (rarely accessed)	Yes	Cheap, portable, power-off when not needed
Expanding a full NAS temporarily	Acceptable	Bridge until you add internal drives
Primary NAS storage	No	Use internal SATA + HBA
Media library for Plex/Jellyfin	Depends	Fine for playback, USB may limit simultaneous streams
ZFS/Unraid array member	No	USB lacks reliable SMART, can disconnect
Time Machine backup target	Yes	External USB drive works well via Samba

External Drive Types

Portable HDDs (2.5”)

Drive	Capacity	Interface	Speed	Power	Price	Notes
WD Elements Portable	1–5 TB	USB 3.0	~130 MB/s	Bus-powered	$50–110	Reliable, basic
Seagate Backup Plus Slim	1–5 TB	USB 3.0	~130 MB/s	Bus-powered	$50–100	Slim design
Toshiba Canvio Advance	1–4 TB	USB 3.0	~130 MB/s	Bus-powered	$45–90	Budget option
Samsung T7 Shield (SSD)	1–4 TB	USB 3.2 Gen 2	~1,000 MB/s	Bus-powered	$80–250	Fast, rugged, SSD

Bus-powered means they draw power from the USB port — no external power adapter needed. Convenient but limited to 2.5” drives (max ~5 TB for HDD).

Desktop HDDs (3.5”)

Drive	Capacity	Interface	Speed	Power	Price	Notes
WD Elements Desktop	4–22 TB	USB 3.0	~180 MB/s	External PSU	$80–350	Often contains WD Red/White drives
Seagate Expansion Desktop	4–18 TB	USB 3.0	~180 MB/s	External PSU	$75–300	Often contains Barracuda/Exos
WD My Book	4–22 TB	USB 3.0	~180 MB/s	External PSU	$90–380	Hardware encryption (can be an issue)

Shucking: Many homelabbers buy these external drives and remove the internal 3.5” HDD for use in a NAS — “shucking.” WD Elements Desktop drives often contain WD Red or White label drives worth more than the external enclosure costs. Check r/DataHoarder for current shuckable models.

WD My Book warning: These drives have hardware encryption on the USB-SATA bridge board. If you shuck the drive, the data is encrypted and inaccessible without the original enclosure. Fine if you plan to reformat the bare drive.

Portable SSDs

Drive	Capacity	Interface	Read/Write	Durability	Price
Samsung T7 Shield	1–4 TB	USB 3.2 Gen 2	1,050/1,000 MB/s	IP65 rated	$80–250
SanDisk Extreme Pro	1–4 TB	USB 3.2 Gen 2	2,000/2,000 MB/s	IP65 rated	$90–260
Crucial X9 Pro	1–4 TB	USB 3.2 Gen 2	1,050/1,000 MB/s	IP55 rated	$70–220
WD My Passport SSD	1–4 TB	USB 3.2 Gen 2	1,050/1,000 MB/s	Drop-resistant	$80–240

Best for: Fast backups, portable storage, offsite backup rotation. The Samsung T7 Shield is the default recommendation — fast, rugged, reliable.

Prices approximate as of February 2026.

Multi-Bay DAS Enclosures

DAS (Direct Attached Storage) enclosures hold multiple drives and connect via USB or Thunderbolt. Not a NAS — they don’t have networking. Your server sees them as directly attached drives.

Enclosure	Bays	Interface	RAID Options	Price	Best For
Mediasonic ProBox HF2-SU31A	4	USB 3.2 Gen 1	None (JBOD)	~$80	Budget 4-bay JBOD
ORICO DS400U3	4	USB 3.0	None (JBOD)	~$70	Budget JBOD, tool-free
TerraMaster D4-300	4	USB 3.1 Gen 1	Hardware RAID 0/1/5/10	~$150	RAID in a DAS
OWC Mercury Elite Pro Dock	4	Thunderbolt 3	SoftRAID support	~$250	Mac/Thunderbolt setups
Sans Digital TR4M6G	4	Mini-SAS (SFF-8088)	None (JBOD)	~$120	HBA-connected JBOD

JBOD vs hardware RAID in a DAS:

JBOD (Just a Bunch Of Disks): Each drive appears as a separate disk to the host. Use software RAID (ZFS, mdadm) on the host. Recommended.
Hardware RAID: The DAS presents one logical volume. Simpler but less flexible. If the DAS controller dies, you may lose access to the RAID. Not recommended for important data.

Why DAS Instead of More Internal Drives?

Your server case is full (mini PC, SFF desktop)
You need drives accessible to swap out (offsite backups)
You want to keep the server and storage physically separate

Why Not DAS?

USB connectivity is less reliable than SATA for 24/7 operation
USB doesn’t support SMART pass-through reliably on all enclosures
Higher latency than internal SATA
An internal HBA card + more drives in a bigger case is almost always better

USB Interface Speeds

Interface	Speed	Connector	Notes
USB 2.0	480 Mbps (60 MB/s)	Type-A	Too slow for anything
USB 3.0 / 3.2 Gen 1	5 Gbps (625 MB/s)	Type-A or C	Fine for HDDs, bottlenecks SSDs
USB 3.1 / 3.2 Gen 2	10 Gbps (1.25 GB/s)	Type-C	Good for SSDs
USB 3.2 Gen 2x2	20 Gbps (2.5 GB/s)	Type-C	Rarely supported
USB4 / Thunderbolt 3	40 Gbps (5 GB/s)	Type-C	Maximum bandwidth, expensive

For HDDs: USB 3.0 is sufficient. A single HDD maxes out at ~200 MB/s — USB 3.0’s 625 MB/s theoretical is plenty. For SSDs: USB 3.2 Gen 2 (10 Gbps) is the minimum for external SSDs. USB 3.0 bottlenecks any SSD faster than 500 MB/s.

Setting Up External Drives on Linux

Mount a USB Drive

# Find the drive
lsblk

# Create mount point
sudo mkdir -p /mnt/external

# Mount (assuming /dev/sdb1)
sudo mount /dev/sdb1 /mnt/external

# Check it's mounted
df -h /mnt/external

Auto-Mount at Boot (fstab)

# Get the drive's UUID (more reliable than /dev/sdX)
sudo blkid /dev/sdb1

# Add to fstab
echo "UUID=your-uuid-here /mnt/external ext4 defaults,nofail 0 2" | sudo tee -a /etc/fstab

The nofail option is critical for external drives — without it, your server won’t boot if the drive is disconnected.

Monitor Drive Health

# Install smartmontools
sudo apt install smartmontools

# Check if SMART works through USB (not always)
sudo smartctl -a /dev/sdb

# If SMART doesn't work through USB, try specifying the bridge
sudo smartctl -a -d sat /dev/sdb

SMART through USB is unreliable — it depends on the USB-SATA bridge chip in the enclosure. This is a key reason why internal SATA is preferred for primary storage.

Set Up Automated Backups to External Drive

Using rsync to back up to an external drive:

# Simple backup script
#!/bin/bash
BACKUP_DEST="/mnt/external/backups"
SOURCE="/path/to/data"
LOG="/var/log/backup.log"

echo "$(date): Backup started" >> "$LOG"
rsync -avh --delete "$SOURCE" "$BACKUP_DEST" >> "$LOG" 2>&1
echo "$(date): Backup completed" >> "$LOG"

Or use Restic or BorgBackup for deduplicated, encrypted backups.

Shucking Guide

Shucking = removing the internal drive from an external enclosure. Why:

External drives are often cheaper per TB than bare internal drives
You get a known-good drive (WD Red, Exos) in a consumer enclosure

How to Shuck

Check the model against shucking databases (r/DataHoarder wiki)
Open the enclosure (usually plastic clips, no screws visible)
Disconnect the SATA/USB bridge board
Remove the bare 3.5” drive
Install in your NAS/server case

The 3.3V Pin Issue

Some shucked WD drives (White Label, some Red) use the SATA 3.3V power pin for a reset function. If the drive doesn’t spin up in your NAS:

Fix 1: Cover pin 3 on the SATA power connector with Kapton tape
Fix 2: Use a Molex-to-SATA power adapter (no 3.3V wire)
Fix 3: Some NAS/motherboards don’t provide 3.3V on SATA power — they work without modification

FAQ

Can I use an external USB drive with ZFS?

Technically yes, but it’s not recommended. ZFS expects stable, always-connected storage. A USB drive that disconnects (even briefly) can corrupt the ZFS pool. Use USB drives as backup targets, not ZFS pool members.

How long do external drives last?

Same as internal drives — 3–5 years typical lifespan for HDDs. SSDs last longer (5–10 years). The weak point is the USB-SATA bridge board, which can fail before the drive itself.

Should I format as ext4 or exFAT?

ext4: Best for Linux-only servers. Journaled, permissions support, reliable.
exFAT: Best if the drive needs to work with Windows and Mac too. No journaling, no permissions.
NTFS: Works on Linux via ntfs-3g but slower. Use if the drive is primarily Windows.

Is USB-C faster than USB-A?

The connector doesn’t determine speed. USB 3.0 (5 Gbps) comes in both Type-A and Type-C. USB 3.2 Gen 2 (10 Gbps) is usually Type-C. Check the spec, not the connector shape.