Seagate · Exos X20 · 512e
ST20000NM000D is Seagate Exos X20 20TB SAS-12G. 3 of its 5 segments are defined in Seagate's published documentation and decoded below; for the rest we have not found a defining document, and they are marked as such. No live listings right now - the reference material below still applies.
| Segment | What it means | Source |
|---|---|---|
| ST | Seagate product prefix. | Seagate |
| 20000 | Capacity field. 20000 denotes 20TB of formatted capacity. | Seagate |
| NM | Enterprise nearline family (Exos and its OEM equivalents). | Seagate |
| 000 | Not sourced - we have not found a Seagate document defining this segment. | Not sourced |
| D | Not sourced - we have not found a Seagate document defining this segment. | Not sourced |
We decode only what the manufacturer documents. There is a large body of community knowledge about the undocumented segments above, much of it probably right, and none of it published by Seagate - so it does not appear in this table. A reading nobody can check does not belong in a column headed “what it means”. Grammar reference: Seagate - product part-number and model-number decoding.
ST20000NM000D is Seagate Exos X20, a 20TB hard drive on SAS-12G. It uses the 512e sector format, which decides whether it will drop into an array or controller expecting the other one. Being a SAS device, it needs a SAS host bus adapter or backplane - it will not run from a motherboard SATA port, though a SATA drive will run on a SAS controller.
We hold no live listing against this exact part number at the moment. 5 sibling part numbers are documented below - these are the numbers most often mistaken for this one, and the table marks which fields actually differ.
| Manufacturer | Seagate |
| Family | Exos X20 |
| Capacity | 20TB |
| Interface | SAS-12G |
| Sector format | 512e |
| Product class | HDD |
These are the part numbers most often confused with ST20000NM000D. The differences below come from the same vendor documentation as the decode above - where a field is not documented, the row leaves it blank rather than guessing.
| Part number | Capacity | Interface | Format | |
|---|---|---|---|---|
| ST20000NM002C | 20TB | SATA-6G | reference | |
| ST20000NM002D | 20TB | SATA-6G | 4Kn | reference |
| ST20000NM002H | 20TB | SATA-6G | in catalogue | |
| ST20000NM003D | 20TB | SAS-12G | in catalogue | |
| ST20000NM007D | 20TB | SATA-6G | in catalogue |
Amber cells differ from ST20000NM000D; grey cells match it.
No seller we track has ST20000NM000D in stock right now. That describes today's listings only - it says nothing about whether the model is discontinued. We are not going to fill this space with something else and call it a match. The decode, specifications and sibling table above are the reference answer for this part number and remain accurate whether or not anyone is selling one today. If you need the capacity rather than this specific part, the alternatives below are what is actually buyable.
A manufacturer part number does not imply a manufacturer warranty, and this is where part-number buyers lose the most money. OEM stock, integrator pulls and gray-market units all reach the market under the maker's own numbering. Retailers selling them sometimes state plainly that the manufacturer warranty is none; others simply do not mention it, which is not the same as it being covered.
Coverage attaches to the individual unit and its serial number, not to the part number. That means the only reliable answer comes from the manufacturer, about the specific drive you are being sold.
Ask the seller for the serial number before purchase, then enter it in Seagate warranty checker. We link the tool rather than showing a result here, because the answer depends on the individual drive and only Seagate can give it.
A seller warranty is a different promise from a different company. What each warranty tier actually covers · Verify on arrival
1 in-stock listing · same capacity and interface, any part number · ranked by live cost per tb, refreshed about once a day
| Drive | Capacity | Interface | Recording | Condition | $/TB | Price | |
|---|---|---|---|---|---|---|---|
| Seagate Exos X20 20TB SAS ST20000NM003D | 20TB | SAS-12G | — | REFURB | $41.45 | $829 | Buy on Amazon |
Every 20TB drive we track, ranked by cost per terabyte.
ST20000NM000D is Seagate Exos X20 20TB SAS-12G. 3 of its 5 segments are defined in Seagate's own published documentation - the decode table on this page shows each one with the document that defines it. For the remaining segments we have not found a defining document, and we say so rather than repeating a community guess as fact.
The part number cannot tell you - coverage follows how the unit entered the market, not its designation. We track no live listing for ST20000NM000D right now, so there is no condition evidence to report either way. Check the specific serial with Seagate's own tool, linked in the warranty section on this page.
ST20000NM000D and ST20000NM002C are both in the Exos X20 range. They differ in interface: SAS-12G against SATA-6G, which decides whether the drive fits your controller. The variant table on this page lists every sibling we document with what differs.
We hold no live listing for this part number right now. That is the honest state rather than a broken page - this remains the reference answer for what ST20000NM000D is, how it decodes and which siblings it is confused with. The alternatives section below shows what is currently buyable at the same capacity.