NAS Drive Compatibility

Western Digital Purple 4TB

Surveillance HDD

Part number WD40EJRX · Purple series · 3.5" SATA HDD. If your machine is listed below, this drive is officially supported — not a forum workaround.

PurpleNAS HARD DRIVE3.5" SATA HDDWESTERN DIGITAL

Part of the Western Digital Purple series →

Check WD40EJRX price on Amazon  partner link

133
Compatible NAS models
125 Syn · 1 QNAP · 7 Asus · 0 TM
By vendor
4 TB
Listed capacity
Western Digital
Manufacturer
Surveillance
Product line (manufacturer rating)
5400
Spindle speed (RPM)
CMR
Recording
256 MB
Cache
180 TB
Rated workload / year

Specifications are the manufacturer's published ratings for this product series; verify the exact part number before purchase.

Strong pick as a cold 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.

Compatibility verdict

It appears on the official compatibility lists of 133 machines and series — 125 Synology, 1 QNAP, 7 Asustor. This is a Surveillance-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

Synology DS1010+5-bay See its full HCL → Synology DS1019+5-bay See its full HCL → Synology DS110+1-bay See its full HCL → Synology DS110j1-bay See its full HCL → Synology DS1111-bay See its full HCL → Synology DS1121-bay See its full HCL → Synology DS112+1-bay See its full HCL → Synology DS112j1-bay See its full HCL → Synology DS1141-bay See its full HCL → Synology DS1151-bay See its full HCL → Synology DS115j1-bay See its full HCL → Synology DS1161-bay See its full HCL → Synology DS1181-bay See its full HCL → Synology DS120j1-bay See its full HCL → Synology DS1511+5-bay See its full HCL → Synology DS1512+5-bay See its full HCL → Synology DS1513+5-bay See its full HCL → Synology DS15155-bay See its full HCL → Synology DS1515+5-bay See its full HCL → Synology DS15175-bay See its full HCL → Synology DS1517+5-bay See its full HCL → Synology DS1520+5-bay See its full HCL → Synology DS1522+5-bay See its full HCL → Synology DS1621+6-bay See its full HCL → Synology DS1812+8-bay See its full HCL → Synology DS1813+8-bay See its full HCL → Synology DS1815+8-bay See its full HCL → Synology DS18178-bay See its full HCL → Synology DS1817+8-bay See its full HCL → Synology DS1821+8-bay See its full HCL → Synology DS2015xs See its full HCL → Synology DS210+2-bay See its full HCL → Synology DS210j2-bay See its full HCL → Synology DS2112-bay See its full HCL → Synology DS211+2-bay See its full HCL → Synology DS211j2-bay See its full HCL → Synology DS2122-bay See its full HCL → Synology DS212+2-bay See its full HCL → Synology DS212j2-bay See its full HCL → Synology DS2132-bay See its full HCL → Synology DS213+2-bay See its full HCL → Synology DS213air2-bay See its full HCL → Synology DS213j2-bay See its full HCL → Synology DS2142-bay See its full HCL → Synology DS214+2-bay See its full HCL → Synology DS214play2-bay See its full HCL → Synology DS214se2-bay See its full HCL → Synology DS215+2-bay See its full HCL → Synology DS215j2-bay See its full HCL → Synology DS2162-bay See its full HCL → Synology DS216+2-bay See its full HCL → Synology DS216+II2-bay See its full HCL → Synology DS216j2-bay See its full HCL → Synology DS216play2-bay See its full HCL → Synology DS216se2-bay See its full HCL → Synology DS2182-bay See its full HCL → Synology DS218+2-bay See its full HCL → Synology DS218j2-bay See its full HCL → Synology DS218play2-bay See its full HCL → Synology DS220+2-bay See its full HCL → Synology DS220j2-bay See its full HCL → Synology DS2232-bay See its full HCL → Synology DS3617xs12-bay See its full HCL → Synology DS3617xsII12-bay See its full HCL → Synology DS4104-bay See its full HCL → Synology DS410j4-bay See its full HCL → Synology DS4114-bay See its full HCL → Synology DS411+4-bay See its full HCL → Synology DS411+II4-bay See its full HCL → Synology DS411j4-bay See its full HCL → Synology DS412+4-bay See its full HCL → Synology DS4134-bay See its full HCL → Synology DS413j4-bay See its full HCL → Synology DS4144-bay See its full HCL → Synology DS414j4-bay See its full HCL → Synology DS415+4-bay See its full HCL → Synology DS415play4-bay See its full HCL → Synology DS4164-bay See its full HCL → Synology DS416j4-bay See its full HCL → Synology DS416play4-bay See its full HCL → Synology DS4184-bay See its full HCL → Synology DS418j4-bay See its full HCL → Synology DS418play4-bay See its full HCL → Synology DS420+4-bay See its full HCL → Synology DS420j4-bay See its full HCL → Synology DS4234-bay See its full HCL → Synology DS423+4-bay See its full HCL → Synology DS710+7-bay See its full HCL → Synology DS712+7-bay See its full HCL → Synology DS713+7-bay See its full HCL → Synology DS7157-bay See its full HCL → Synology DS716+7-bay See its full HCL → Synology DS716+II7-bay See its full HCL → Synology DS718+7-bay See its full HCL → Synology DS720+7-bay See its full HCL → Synology DS723+7-bay See its full HCL → Synology DS918+4-bay See its full HCL → Synology DS920+4-bay See its full HCL → Synology DS923+4-bay See its full HCL → Synology DVA1622 See its full HCL → Synology DVA3219 See its full HCL → Synology DVA3221 See its full HCL → Synology RS1219+ See its full HCL → Synology RS212 See its full HCL → Synology RS214 See its full HCL → Synology RS217 See its full HCL → Synology RS3617RPxs See its full HCL → Synology RS3617xs+ See its full HCL → Synology RS3618xs See its full HCL → Synology RS4017xs+ See its full HCL → Synology RS411 See its full HCL → Synology RS810+ See its full HCL → Synology RS810RP+ See its full HCL → Synology RS812 See its full HCL → Synology RS812+ See its full HCL → Synology RS812RP+ See its full HCL → Synology RS814 See its full HCL → Synology RS814+ See its full HCL → Synology RS814RP+ See its full HCL → Synology RS815 See its full HCL → Synology RS815+ See its full HCL → Synology RS815RP+ See its full HCL → Synology RS816 See its full HCL → Synology RS818+ See its full HCL → Synology RS818RP+ See its full HCL → QNAP TS-451D2 See its full HCL → Asustor AS 10 See its full HCL → Asustor AS 31/32 See its full HCL → Asustor AS 50/51 See its full HCL → Asustor AS 61/62 See its full HCL → Asustor AS 63/64 See its full HCL → Asustor AS 70 See its full HCL → Asustor AS6004U See its full HCL →

Same-capacity alternatives

Other drives listed at 4 TB capacity, ranked by how many machines list them:

Toshiba MG04ACA400E 451 machines · MG04ACA**** Western Digital WD4003FFBX 390 machines · Red Pro Seagate ST4000NE0015 379 machines · Enterprise NAS HDD Toshiba MG04ACA400N 353 machines · MG04ACA**** Western Digital WD40PURZ 352 machines · Purple Seagate ST4000NM002A 346 machines · Exos 7E8 Seagate ST4000NE0025 344 machines · IronWolf Pro Western Digital HUS726T4TALA6L4 333 machines · Ultrastar 7K6

Quick answers

Is the WD40EJRX officially compatible with my NAS?

It appears on the official compatibility lists of 133 machines and series — 125 Synology, 1 QNAP, 7 Asustor. Every machine page linked below shows the vendor's own list entry, refreshed daily.

Is the WD40EJRX CMR or SMR?

As a Western Digital Purple 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 WD40EJRX a good NAS drive?

This is a Surveillance-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 WD40EJRX 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 WD40EJRX?

At the same capacity, the most widely listed alternatives are Toshiba MG04ACA400E (451 machines), Western Digital WD4003FFBX (390 machines), Seagate ST4000NE0015 (379 machines). The full ranked list is below.