Exos is Seagate's enterprise nearline line, and for a home NAS it is frequently the cheapest way to buy capacity — it often undercuts NAS-branded drives per terabyte. The cheapest Exos we track right now is $29.17/TB. Two things to check before buying: the interface, because Seagate ships the same capacities in SATA and SAS and a SAS drive will not work on a SATA-only backplane, and the condition track, because the refurbished market for Exos is one of the deepest in storage.
Prices updated · live figures update every 4-5 hours · 3 of 12 in-stock rows are SAS
Live prices · updated every 4-5 hours · last checked 2 min ago · ranked by live cost per terabyte; interface shown per row because SAS will not work on a SATA-only backplane
| Model | Capacity | Recording | RPM | Workload TB/yr | Warranty | $/TB | Price | |
|---|---|---|---|---|---|---|---|---|
| 24TB ST24000NM002HREFURB | 24TB | CMR | 7,200 | 550 | 5 yr | $29.17 | $700 | Buy |
| 22TB ST22000NM001E | 22TB | CMR | 7,200 | — | 5 yr | $29.55 | $650 | Buy |
| 20TB ST20000NM007DREFURB | 20TB | CMR | 7,200 | — | 5 yr | $33.50 | $670 | Buy |
| 18TB ST18000NM003D | 18TB | EPMR | 7,200 | 550 | 5 yr | $37.55 | $676 | Buy |
| 16TB ST16000NM002GREFURB | 16TB | CMR | 7,200 | 550 | 5 yr | $39.84 | $637 | Buy |
| 24TB ST24000NM002H | 24TB | CMR | 7,200 | 550 | 5 yr | $40.00 | $960 | Buy |
| 20TB ST20000NM002H | 20TB | CMR | 7,200 | — | 5 yr | $40.00 | $800 | Buy |
| 30TB ST30000NM004K | 30TB | CMR | 7,200 | 550 | 5 yr | $40.00 | $1200 | Buy |
| 14TB ST14000NM0018 | 14TB | CMR | 7,200 | 550 | 5 yr | $42.86 | $600 | Buy |
| 20TB ST20000NM003DREFURB | 20TB | CMR | 7,200 | — | 5 yr | $43.05 | $861 | Buy |
| 12TB ST12000NM002G | 12TB | CMR | 7,200 | 550 | 5 yr | $45.37 | $544 | Buy |
| 24TB ST24000NM000H | 24TB | CMR | 7,200 | 550 | 5 yr | $58.37 | $1401 | Buy |
Workload rating is recorded per part number from Seagate's datasheet for that exact model, not blanketed across the line — two drives of the same capacity can differ because they are different generations. A dash means the figure is not stated for that listing. Recording technology comes from the manufacturer's published CMR/SMR list; a model absent from that list is shown as UNVERIFIED rather than guessed. Rows priced above 3× this line's in-stock median are flagged and excluded from the winner callout and from every median we compute.
Both tracks, live, at every capacity where we hold a price for each. A capacity with only one track shows that track and a dash for the other — we never imply a saving we cannot compute from two live prices. 2 of 8 capacities currently have both.
| Capacity | Best new | Best refurb | Refurb saves |
|---|---|---|---|
| 12TB | $544 ($45.37/TB) | — | — |
| 14TB | $600 ($42.86/TB) | — | — |
| 16TB | — | $637 ($39.84/TB) | — |
| 18TB | $676 ($37.55/TB) | — | — |
| 20TB | $800 ($40.00/TB) | $670 ($33.50/TB) | 16% |
| 22TB | $650 ($29.55/TB) | — | — |
| 24TB | $960 ($40.00/TB) | $700 ($29.17/TB) | 27% |
| 30TB | $1200 ($40.00/TB) | — | — |
Scalper-priced listings are excluded from both “best” columns, as they are from every aggregate on this site. Live figures update every 4-5 hours.
Built from the rows we actually track, so a generation only appears if it is in the catalogue. The X number is a platform generation, not a capacity — X16 spans several capacities and is not necessarily a 16TB drive.
| Generation | Capacities tracked | Interfaces | Sector format | Recording | In stock |
|---|---|---|---|---|---|
| Exos (ungenerationed) | 12TB, 16TB | SASSAS | 512e | CMR | 2 |
| X14 | 14TB | SATA | 512e | CMR | 1 |
| X16 | 16TB | SATA | 512e | CMR | 0 |
| X20 | 18TB, 20TB | SATA / SASSAS | 512e | ePMR, CMR | 4 |
| X22 | 22TB | SATA | 512e | CMR | 1 |
| X24 | 24TB | SATA | 512e | CMR | 3 |
| Mozaic / HAMRFRONTIER | 30TB, 32TB | SATA | 512e | CMR | 1 |
A SAS drive will not work in a SATA-only backplane or on a desktop SATA port. The reverse is fine — a SAS backplane accepts SATA drives. Seagate ships the same capacities in both interfaces under very similar names, which is the most expensive confusion on this line.
Exos is Seagate's enterprise nearline hard drive line - the drives that go into datacentre racks by the pallet. They are built for continuous duty in multi-drive enclosures, they are rated for a workload figure Seagate publishes per model, and they are the volume product that funds the rest of the company's drive business.
For a home or small-office buyer the interesting thing about that is not the engineering. It is the pricing. Because Exos sells in enormous volume to buyers who negotiate hard, and because the same drives reach retail through both new and decommissioned-fleet channels, Exos frequently lands below NAS-branded drives of the same capacity on cost per terabyte. That is the arbitrage this page is about, and the tables below either demonstrate it today or they do not - we let the live numbers answer.
What you give up relative to a NAS-branded drive is mostly firmware tuning intended for small arrays and, depending on the model, some vibration-handling features aimed at desktop enclosures. What you gain is capacity per pound and a workload rating that is usually higher, not lower, than the consumer NAS line.
The X number is a generation marker rather than a capacity: X14, X16, X18, X20, X22 and X24 are successive platform generations, and each spans several capacities. A drive labelled X16 is not necessarily 16TB, though the numbers frequently coincide at the top of a generation, which is the source of most of the confusion.
Later generations bring higher areal density, which is how the capacity ceiling climbs. For a buyer the practical consequence is narrow: a newer generation at the same capacity is usually a slightly newer design at a similar price, and the decision is almost always made on price per terabyte and interface rather than on generation.
The decoder table on this page is built from the rows we actually track, so a generation only appears if it is in our catalogue. That is deliberate - a decoder listing generations we cannot price would be a specification sheet rather than a buying tool.
Above the X-series sits Seagate's HAMR-based platform, marketed as Mozaic, at 30TB and 32TB in our catalogue. Heat-assisted magnetic recording increases areal density by writing to more magnetically stable media, which is how these capacities exist at all.
They are shipping and we track them, but the frontier is expensive per terabyte and the catalogue is thin - a handful of rows, not a market. Our HAMR reality check report puts numbers on both of those and reaches an unflattering conclusion for anyone shopping on value: the frontier currently carries a substantial premium over the mainstream capacity band.
Buy the frontier if you are bay-constrained rather than budget-constrained. Everyone else should read the per-terabyte column on the table above and buy the middle of the range.
Seagate ships the same Exos capacities in both SATA and SAS, under names that differ by very little. This is the single most expensive confusion on the line, and it is entirely avoidable.
A SAS drive will not work in a SATA-only backplane or on a desktop motherboard's SATA ports. The connector is keyed to prevent it and no adapter resolves it in a hot-swap bay. The reverse is fine: a SAS backplane accepts SATA drives, which is standard and designed in, and it is the reason a used enterprise chassis can be filled with cheap SATA capacity.
So: if the drive is going into a desktop, a consumer NAS, or a SATA-only enclosure, you need the SATA part. If it is going into an enterprise chassis with a SAS backplane, either will work and SAS is often cheaper second-hand because the pool of buyers is smaller. Every table on this page shows the interface per row, and SAS rows are marked, because a listing title frequently does not make it obvious.
Where Seagate's datasheet states a sector format for a model we track, it appears in the decoder. Most Exos drives sold at retail are 512e, which emulates the 512-byte sectors older software expects while using 4K physical sectors underneath. Some enterprise parts, particularly on the SAS side, are native 4Kn.
For most buyers this does not matter: modern operating systems handle both. It matters if you are adding a drive to an existing array that was built on one format, or running older software with assumptions about sector size. Where our seeded data does not state the format, the cell is blank rather than filled with a guess.
Exos is one of the deepest refurbished markets in storage, because the drives are decommissioned from fleets in large batches. The dual-track ladder on this page shows both conditions at each capacity where we hold live prices for both, with the spread computed from those two live figures rather than from a list price.
The trade is the usual one: shorter warranty, unknown powered-on hours, and a price that is frequently a fraction of new. For an array with real redundancy and monitoring that is often the right buy, and our recertified drive guide covers what the grades mean and what to check on arrival.
One caveat specific to enterprise drives: a refurbished Exos has been running continuously in a datacentre, which is a harder life than a desktop drive has had but also exactly the duty cycle it was designed for. High powered-on hours with clean SMART counters are not the warning sign they would be on a consumer drive.
Warranty length for each model we track comes from Seagate's own documentation and is shown per row where we hold it. Enterprise nearline drives typically carry longer coverage than consumer lines, and that is part of what the price buys on the new track.
A refurbished drive's warranty comes from the seller rather than from Seagate, and the terms vary widely. That is a question to settle before purchase rather than a specification you can look up, and it is the main reason the two tracks are not interchangeable even when the hardware is identical.
We publish no failure-rate figures for any drive on this site. We have not run a fleet study, published field data is not ours to restate as our own, and a reliability number attached to a model rather than a population is not information a buyer can act on.
Two head-to-heads matter for this line. Against IronWolf is the home-NAS question: whether the enterprise drive undercuts the NAS-branded one at your capacity, computed live rather than asserted. Against WD Ultrastar is the enterprise head-to-head — the two deepest enterprise catalogues on this site, with both condition tracks on both sides.
For the frontier capacities, our HAMR reality check puts a number on the Mozaic premium. For filling an enterprise chassis with these drives, the used server guides cover which backplane you are buying — which is the same SATA-versus-SAS question from the other direction.
Each of these carries the same live pricing and, where the family mixes recording technologies or interfaces, the same per-model decoder.
CMR drive list · Recertified guide · NAS devices · External drives
Yes, and it is one of the more sensible things you can do with a NAS that takes standard drives. Exos is enterprise nearline hardware built for continuous duty in multi-drive enclosures, with a workload rating usually higher than the consumer NAS line. What you give up is firmware tuning aimed at small arrays and, on some models, vibration features intended for desktop enclosures. What you gain is capacity per pound, which is frequently substantial.
Often, and the tables on this site compute it live rather than asserting it. Because Exos sells in enormous volume and reaches retail through both new and decommissioned-fleet channels, it frequently undercuts NAS-branded drives at the same capacity on cost per terabyte. Our IronWolf versus Exos comparison puts the current numbers side by side; the answer changes with stock, which is why it is computed rather than written.
They are successive platform generations, not capacities. Each X number spans several capacity points, and a newer generation brings higher areal density - which is how the capacity ceiling climbs over time. For a buyer the difference at the same capacity is usually small enough that price per terabyte and interface decide the purchase, not the generation number.
Almost certainly not. SAS drives need a SAS controller or backplane; they will not work on a desktop motherboard's SATA ports or in a SATA-only enclosure, and the connector is keyed to prevent the mistake. The reverse works fine - a SAS backplane accepts SATA drives. Seagate ships the same Exos capacities in both interfaces under very similar names, so check the interface column before buying. Every table on this site shows it per row.
For an array with real redundancy and monitoring, usually yes, and Exos has one of the deepest refurbished markets in storage because the drives come out of fleets in batches. You accept a shorter, seller-provided warranty and unknown powered-on hours. Worth knowing: high hours with clean SMART counters mean less on an enterprise drive than they would on a consumer one, because continuous duty is the workload it was designed for.
Those are Seagate's HAMR-based platform, marketed as Mozaic. Heat-assisted recording raises areal density, which is how those capacities exist. They ship and we track them, but the catalogue is thin and they carry a substantial premium per terabyte over the mainstream band - our HAMR reality check report quantifies it. They make sense if you are bay-constrained; if you are shopping on value, buy the middle of the range.
It is the sector format. 512e presents 512-byte sectors to software while using 4K sectors physically; 4Kn is native 4K throughout. Modern operating systems handle both, so for most buyers it does not matter. It matters when you are adding a drive to an array built on one format, or running older software with sector-size assumptions. Where Seagate's datasheet states the format for a model we track, it is in the decoder; where it does not, the cell is blank rather than guessed.
Every table on this page reads our live catalogue and refreshes every few hours. The timestamp shown is the last successful refresh rather than the moment you loaded the page - a freshness date that moves on every reload tells you nothing about the data behind it. Out-of-stock listings are excluded from the tables rather than shown with a stale price.
Specification claims on this page were checked against the pages below on 4 August 2026. Where a widely-repeated figure did not survive that check, we report what the source says now and say so in the text rather than repeating the familiar number.