Seagate EXOS x20 20TB
Enterprise HDD
Part number ST20000NM002D · EXOS x20 series · NL-SAS 12Gb/s. If your machine is listed below, this drive is officially supported — not a forum workaround.
Check ST20000NM002D price on Amazon partner link
No series-level recording rating is on file for this part number yet — check the exact model for CMR vs SMR before buying it as a large cold copy (SMR is the one trait that makes a 16 TB+ backup copy painfully slow). The 3-2-1 guide and the backup tools encyclopedia cover what to schedule it with.
Compatibility verdict
It appears on the official compatibility lists of 5 machines and series — 4 QNAP, 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. No series-level recording rating is on file for this part number yet, so check CMR vs SMR on the exact model before buying for an array.
Compatible NAS models
Same-capacity alternatives
Other drives listed at 20 TB capacity, ranked by how many machines list them:
Quick answers
Is the ST20000NM002D officially compatible with my NAS?
It appears on the official compatibility lists of 5 machines and series — 4 QNAP, 1 Asustor. Every machine page linked below shows the vendor's own list entry, refreshed daily.
Is the ST20000NM002D 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. No series-level recording rating is on file for this part number yet, so check CMR vs SMR on the exact model before buying for an array.
Can I use the ST20000NM002D for a 3-2-1 cold backup copy?
No series-level recording rating is on file for this part number yet — check the exact model for CMR vs SMR before buying it as a large cold copy (SMR is the one trait that makes a 16 TB+ backup copy painfully slow). The 3-2-1 guide and the backup tools encyclopedia cover what to schedule it with.
What are alternatives to the ST20000NM002D?
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.