WD20EFAX - CMR or SMR?

SMR

The WD WD Red 2TB (WD20EFAX) uses SMR recording.

Verified against: Western Digital internal client HDD recording technology - SMR drives by capacity (7 July 2020) · Checked

Sources disagree on this model

One of the WD Red models at the centre of the 2020 undisclosed-SMR episode, which led to litigation and to WD publishing this list. WD Red Plus is the conventionally-recorded replacement line.

What this means for you

Shingled recording overlaps tracks like roof tiles to raise density. Reading is unaffected, and for sequential work, archives, media libraries, backup targets, files written once and read many times, this drive is genuinely fine and the saving is real. The problem is sustained random writing, because modifying data under an existing track can force the tracks above it to be rewritten too. A RAID rebuild or a ZFS resilver is hours of exactly that pattern with no idle time to recover, so a 2TB WD20EFAX in an array can extend a rebuild dramatically, and the rebuild window is precisely when the array has no redundancy left. Do not put this drive in a NAS or a parity array.

Specifications

Model numberWD20EFAX
BrandWD
FamilyWD Red
Capacity2TB
Form factor3.5"
Rotational speed5400 RPM
Cache256 MB
Recording technologySMR
Workload rate
Warranty
StatusDiscontinued
Replaced by

A dash means the manufacturer does not state that field for this exact model. We leave it blank rather than filling it from a retailer listing.

Need CMR at this capacity?

If this drive is going into an array, a NAS, or anything that rebuilds, shingled recording is the wrong choice at any price. These are conventionally-recorded drives at this capacity or one step up, in stock right now with live prices.

DriveCapacityRecording$/TBPrice
MG03SCA200 2TB SAS 6G2TBCMR$22.00$44Buy
P2000 2TB SAS 6G 7.2K2TBCMR$34.49$69Buy
2TB SATA 6G 7200RPM2TBCMR$50.00$100Buy

Verified CMR model numbers at this size: ST2000VX008, ST2000VN004, DT01ACA200, HDWD120.

Related models

Other WD Red capacities
WD30EFAX3TBSMRWD40EFAX4TBSMRWD60EFAX6TBSMR
The same capacity from other makers
ST2000DM0062TBCMRST2000DX0022TBCMRST2000VX0082TBCMR
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Frequently asked questions

Is the WD20EFAX CMR or SMR?

It is SMR. That comes from Western Digital internal client HDD recording technology - SMR drives by capacity (7 July 2020), which is WD's own documentation for this exact part number rather than a capacity-level summary or a retailer listing.

Can I use the WD20EFAX in a NAS or RAID array?

We would not. Shingled recording turns a rebuild into hours of the write pattern it handles worst, which can extend the window during which your array has no redundancy. For sequential and archival use outside an array this drive is fine.

What should I buy instead of the WD20EFAX for a NAS?

A conventionally-recorded drive at 2TB or one step up. The table above lists what is in stock right now with live prices, and every model number linked there has its own verified page with the manufacturer source.

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