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StashRaid

Storage Parameters

Usable Capacity

12 TB

Fault Tolerance

4

Array Resilience

Architecture

RAID 5 • Parity

Fault Tolerance

1 Concurrent Failures Allowed

Current Configuration

RAID 5 (Parity)

12 TB Usable

Total RAW: 16 TB

Disk 01DATA
Disk 02DATA
Disk 03DATA
Disk 04PARITY

Total Drives

4 x 4 TB

Efficiency

75% Utilized

Usable: 12 TBWasted to redundancy: 4 TB

Pros & Cons

  • PRO: Good balance of capacity/speed/safety

  • PRO: Cost-effective redundancy

  • CON: Slower writes due to parity calculation

    This setup prioritizes redundancy but has associated performance or capacity costs.

Used & Refurbished Enterprise Drive Guide

Buying used enterprise drives can save 50–70% off retail — but only if you vet them properly. This guide covers where to buy, which SMART attributes to check, the burn-in procedure with real CLI commands, and when the savings are worth the risk.

Where to Buy Used Drives

Stick to known refurbishers with clear return policies. Always demand SMART data before purchase.

SellerPrice vs RetailWarrantyNotes
ServerPartDeals50–65%90 d – 2 yrBest reputation; publishes SMART data; easy returns
goHardDrive45–60%90 d – 1 yrLarge inventory; mixed feedback on packaging
eBay (reputable sellers)40–70%30 d (eBay guar.)Check >98% rating, >1,000 sales
Reddit r/homelabsales35–55%NoneCheapest, zero warranty; demand CrystalDiskInfo screenshot

Listing Red Flags

No SMART data published — walk away.

POH over 50,000 without a steep discount.

Return period under 30 days — you need time to burn in.

Consumer models (Barracuda, WD Blue) — buy enterprise (Exos, Ultrastar, MG-series).

SMART Attributes to Check Before You Buy

Screen every candidate drive against these thresholds. Any non-zero value in the critical columns is grounds for rejection. Use smartctl -a /dev/sdX to view all attributes.

IDAttributeThresholdWhy It Matters
05Reallocated Sectors Count0 — any non-zero is suspiciousBad sectors already remapped. Any ≥1 means the drive is degrading. Hard pass for RAID use.
09Power-On Hours (POH)< 30,000 ideal; < 50,000 acceptableEnterprise drives rated 1.2–2.5M h MTBF. Above 50,000 h AFR rises notably.
0CPower Cycle Count< 100 / year of operationFrequent cycling stresses spindle motors. High count = worn mechanics.
B8End-to-End Error0Data-in-flight errors inside the drive. Non-zero = internal data path issues.
BBReported Uncorrectable0Sectors uncorrectable after retries. Any non-zero = media damage.
BEAirflow Temp (difference)< 5°C from ambientHigh delta = poor ventilation in source chassis; drive may have cooked.
C2Temperature (current / max)Current < 45°C; Max < 60°CSustained >50°C drastically reduces lifespan. Max 65°C+ is a hard pass.
C4Reallocation Event Count0 — any equals badEach event causes RAID performance hiccup. Multiple events = drive on borrowed time.
C5Current Pending Sector0Sectors awaiting reallocation. Unstable — might fail on next write. Hard pass.
C6Offline Uncorrectable0Sectors failed during offline scan. Growing count = actively failing drive.
187Reported Uncorrectable Errors0Same as BB — vendor-specific encoding. Non-zero = bad.
188Command Timeout0Commands timed out during operation. Suggests internal firmware/mechanics issues.
197Current Pending Sector Count0Duplicate of C5 on some vendors. Non-zero = unstable medium.
198Uncorrectable Sector (Offline)0Duplicate of C6. Non-zero = failing media.

Burn-In Procedure

Always burn in used drives before deployment. A proper burn-in catches early failures — the bathtub curve means most defects appear in the first 48 hours of operation. Expect 24–72 hours per drive.

1Visual Inspection

Check the SATA/SAS connector for bent pins, the PCB for corrosion or burn marks, and the label for tampering or mismatched model numbers. A drive that looks damaged is damaged — don’t even plug it in.

2Short SMART Test

smartctl -t short /dev/sdX(~2 min). Quick health check — confirms the drive responds to commands and passes basic diagnostics.

3Full SMART Long Test

smartctl -t long /dev/sdX(6–12 h for 12–18 TB). Check result with smartctl -l selftest /dev/sdX. Must show “Completed without error.”

4Badblocks (Destructive or Non-Destructive)

badblocks -wsv -b 4096 -c 65536 /dev/sdX(1–2 days, destructive). Any bad blocks = return the drive.
badblocks -sv -c 65536 /dev/sdX(non-destructive, for drives with data).

5Monitor SMART During Burn-In

smartctl -A /dev/sdXRun this during and after badblocks. If reallocated sectors or pending sectors increase during the burn-in, the drive is actively failing and should be returned.

6Verify Speed

hdparm -tT /dev/sdXExpect >180 MB/s for modern enterprise HDDs. Much lower suggests interface issues or drive degradation.

Pro tip: Launch one badblocks per drive in separate tmux sessions. A 16-drive batch takes 2–3 days — no need to sequence them.

When Are the Savings Worth It?

Use CaseVerdictReason
Cold / backup RecommendedPowered off most of the time — POH matters less.
Media server (Plex) RecommendedRead-heavy sequential workload. Used Exos/Ultrastar excel.
Primary RAID-5/6 CautiousOne failure triggers rebuild stress. Keep a hot spare.
ZFS with redundancy CautiousScrub frequency increases. Checksumming helps, but failure risk is higher.
Critical business data AvoidBuy new with 5-year warranty. 50% savings don't justify data loss.

The 50–70% Off Rule

A used drive should cost no more than 50–70% of retail for a new equivalent. With 30,000 POH you get 2–3 useful years vs 5+ for new. If the used price is >60% of new, new wins on cost-per-year.

Enterprise SAS vs Consumer SATA for Used Buys

SAS enterprise drives (Exos, Ultrastar, MG-series) are built to higher specs — helium fill, dual actuators on newer models, TLER/ERC out of the box. They come from data center decomms with documented SMART. Consumer SATA (Barracuda, WD Blue) often have unknown power/temperature history and lack vibration tolerance.

The catch: SAS needs an HBA ($30–60). Most NAS users already have or want one for direct disk control. Factor the HBA cost into your savings.

WARNING: SMR in Used Drives

Shingled Magnetic Recording (SMR) drives still flood the used market as “archive” models. They are not suitable for RAID or ZFS. Write speeds can drop to 10–40 MB/s and rebuild times stretch from hours to days.

Avoid: Seagate Archive (ST8000AS0002, ST8000DM004), WD Red (non-Pro EFAX), any “archive” or “backup” model.

Check: smartctl -a /dev/sdX | grep -i "SMR\|shingled\|zoned"

See our CMR vs SMR Guide for the full breakdown.

Related Guides & Tools

CMR vs SMR Guide

Why SMR fails in RAID and how to spot it.

Drive Failure Math

AFR, MTBF, and bathtub curves for used drives.

Rebuild Time Guide

How long will your degraded array run with used drives?

Gear Recommender

Find the right drive class for your workload.

FAQ

Are used enterprise drives safe for a home NAS?

Yes — if you vet SMART data, run a full badblocks burn-in, and buy from a seller with a return policy. A used Exos with 30,000 POH is often more reliable than a new consumer drive.

What POH is too high for a used drive?

Under 30,000 hours (~3.4 years) is ideal for RAID. 30,000–50,000 is acceptable for cold storage or media servers. Above 50,000 h AFR climbs. Avoid over 60,000 h unless very cheap with solid backups.

Can I mix used and new drives in the same RAID array?

Yes, but cautiously. A used drive that fails early triggers a rebuild on all others. Keep a hot spare, or better, place used drives in a separate vdev/pool.

How do I spot SMR drives when buying used?

Check the model against CMR/SMR databases. Avoid 'Archive' series, WD Red (non-Pro EFAX), Seagate DM/DV. After purchase run 'smartctl -a | grep -i zoned' — if ZBD appears, it's SMR.

What is the 50–70% off rule for used drives?

A used drive should cost no more than 50–70% of retail for new equivalent. With 30,000 POH you get 2–3 useful years vs 5+ for new. If the used price is >60% of new, buying new wins on cost-per-year.

Prices approximate. Always verify seller reputation, return policies, and your backup strategy before buying used storage.