Seagate Exos X20 20 TB
Enterprise HDD
Part number ST20000NM000D · Exos X20 series · 3.5'' SATA HDD. If your machine is listed below, this drive is officially supported — not a forum workaround.
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Specifications are the manufacturer's published ratings for this product series; verify the exact part number before purchase.
Rated CMR (conventional magnetic recording) — the right recording type for a large cold copy. CMR keeps a full-library backup pass fast even at 16–24 TB, which is the whole point of the offline slot in a 3-2-1 plan: rotate two drives monthly, keep one powered off, and the backup tooling (Veeam, Duplicati, Hyper Backup, HBS 3) does the scheduling. Full rule and vendor tool table: 3-2-1 for NAS.
Compatibility verdict
It appears on the official compatibility lists of 1 machines and series — 1 Asustor. This is a Enterprise-class drive: rated for heavier sustained workloads than desktop drives. It is a strong pick for a NAS running 24/7, large-array rebuilds or camera workloads, and enterprise lines are also the drives most widely listed across all five vendors' HCLs. Its series rating is on file as CMR (conventional) — what RAID rebuilds and full-library copies want.
Compatible NAS models
Same-capacity alternatives
Other drives listed at 20 TB capacity, ranked by how many machines list them:
Quick answers
Is the ST20000NM000D officially compatible with my NAS?
It appears on the official compatibility lists of 1 machines and series — 1 Asustor. Every machine page linked below shows the vendor's own list entry, refreshed daily.
Is the ST20000NM000D CMR or SMR?
As a Seagate Exos X20 drive, it is rated CMR. CMR (conventional magnetic recording) is what a RAID array wants: SMR drives slow rebuilds dramatically. See the <a href="/faq/cmr-vs-smr-nas-drives/">CMR vs SMR guide</a> for the full series table.
Is the ST20000NM000D a good NAS drive?
This is a Enterprise-class drive: rated for heavier sustained workloads than desktop drives. It is a strong pick for a NAS running 24/7, large-array rebuilds or camera workloads, and enterprise lines are also the drives most widely listed across all five vendors' HCLs. Its series rating is on file as CMR (conventional) — what RAID rebuilds and full-library copies want.
Can I use the ST20000NM000D for a 3-2-1 cold backup copy?
Rated CMR (conventional magnetic recording) — the right recording type for a large cold copy. CMR keeps a full-library backup pass fast even at 16–24 TB, which is the whole point of the offline slot in a 3-2-1 plan: rotate two drives monthly, keep one powered off, and the backup tooling (Veeam, Duplicati, Hyper Backup, HBS 3) does the scheduling. Full rule and vendor tool table: 3-2-1 for NAS.
What are alternatives to the ST20000NM000D?
At the same capacity, the most widely listed alternatives are Toshiba MG10ACA20TE (144 machines), Toshiba MG11ACA20TE (135 machines), Toshiba MG10ACA20TA (133 machines). The full ranked list is below.