WD Ultrastar DC: Reading the Model Number, From HC560 to HC590

How to read a WD Ultrastar DC model number

WD prints a key on its data sheets, so a model number here can be decoded rather than guessed at. The fullest key we read is on the Ultrastar DC HC590 sheet, written as WUH7226XXALxxyz. Each meaning below is WD's own, from that sheet.

• W is Western Digital, U is Ultrastar, H is Helium (S would mean Standard) and 72 is 7200 RPM.
• 26 is the maximum capacity and XX is the capacity of this model.
• A is the generation code, and the L straight after it means a 26.1 mm z-height.
• xx is the interface: E6 is 512e SATA 6 Gb/s and 52 is 512e SAS 12 Gb/s.
• y is Power Disable Pin 3 status: 0 means supported, L means the legacy Pin 3 configuration with no Power Disable.
• z is the data security mode: 0 is Instant Secure Erase, 1 is SED TCG-Enterprise, 4 is Base (SE) with no encryption and 5 is SED-FIPS.

Two cautions before you apply it. L has two meanings depending on where it sits, once for height and once for Pin 3. And this key belongs to the HC590. The HC560 sheet confirms E6, the 4 for Base (SE) and the Pin 3 value 0, but its 5.8 W SATA models carry a B where this key shows A, as in WUH722020BLE6L4. We have not found a WD document that defines that B, so we leave it undefined.

Ultrastar DC HC560 20TB: part number and datasheet figures

The WD Ultrastar DC HC560 delivers 20 TB on a nine-disk platform at 2.2 TB per platter, in CMR. WD's sheet gives a workload of up to 550 TB a year. If you searched by the ordering code 0F38785, the sheet's footnote ties it to model WUH722020BLE6L4, and its sibling 0F38784 to WUH722020BLE6L1.

On the HC560 key, E6 in WUH722020BLE6L4 means 512e SATA 6 Gb/s and the final 4 means a Base (SE) drive with no encryption. Idle power depends on the model letter and interface: the WUH722020BLE6L SATA models list 5.8 W, while the WUH722020ALE6L models and the SAS models list 6.1 W. Two drives sold as a 20 TB Ultrastar can therefore differ by 0.3 W at idle.

The live table holds 3 WD Ultrastar 20TB rows, from £52.90/TB. If a row's part number does not begin WUH722020, the HC560 figures above do not describe it. The broader 20 TB hard drive choice takes in other makers.

WD Ultrastar DC HC570 22TB: SATA SE and SED part numbers

The HC570 delivers 22 TB in CMR and is designed for workloads up to 550 TB per year. Its model numbers are WUH722222ALE6L1 and WUH722222ALE6L4 on SATA, with WUH722222AL5201 and WUH722222AL5204 on SAS. WD also lists four part numbers, two for each interface. A search for the WD Ultrastar DC HC570 22TB SATA SE means 0F48155, the Base SE SATA part.

22 TB is not exclusive to this model, because the HC580 lists it too, as WUH722422 numbers against the HC570's WUH722222. A 22 TB Ultrastar row is therefore not automatically an HC570. The table holds 2 rows at this capacity, from £44.55/TB, and the part number column settles which generation each one is.

Ultrastar DC HC580 data center HDD: 24TB and 22TB

The HC580 reaches 24 TB in a CMR recording format, with a workload of up to 550 TB a year. WD's sheet splits it into these models and part numbers. On SAS we give the part numbers by capacity only, without matching each to a model.

• 24 TB SATA: WUH722424ALE6L1 and WUH722424ALE6L4, part numbers 0F62795 (SED) and 0F62796 (Base SE).
• 22 TB SATA: WUH722422ALE6L1 and WUH722422ALE6L4, part numbers 0F62784 (SED) and 0F62785 (Base SE).
• 24 TB SAS: WUH722424AL5201 and WUH722424AL5204, part numbers 0F62801 and 0F62802.
• 22 TB SAS: WUH722422AL5201 and WUH722422AL5204, part numbers 0F62790 and 0F62791.

Idle power is 5.5 W on SATA and 5.8 W on SAS at either capacity, so the larger drive wins per terabyte. WD states 0.23 W/TB for 24 TB SATA against 0.25 W/TB for 22 TB SATA, and 0.24 W/TB against 0.26 W/TB on SAS. Typical acoustics are 2.0 Bels at idle and 3.2 Bels operating.

Ultrastar DC HC590: 26TB and 24TB, with projected ratings

The HC590 comes as 24 TB and 26 TB, each on SATA 6 Gb/s or SAS 12 Gb/s, with the model number formats WUH722624ALxxyz and WUH722626ALxxyz. All four variants are CMR, built on an 11-disk platform, and offer 512e and 4Kn sectors. WD rates them for 550 TB a year.

Projected, not final: WD's sheet lists the HC590 at 2.5 million hours MTBF (projected) and a 0.35% annualised failure rate (projected), and says final figures will be based on a sample population. The sheet also lists 24x7 availability and a 5-year limited warranty.

On transfer, WD gives a sustained rate of 287 MB/s at 24 TB and 302 MB/s at 26 TB, with interface limits of 600 MB/s on SATA and 1200 MB/s on SAS. Writing a whole drive at those sustained maximums takes about 23.2 hours at 24 TB and 23.9 hours at 26 TB. That is our arithmetic and a floor, so an actual rebuild will not beat it.

Idle power does not change between the two capacities, and WD states 0.22 W/TB for 26 TB SATA. Under WD's stated load, random 50/50 read and write at 4KB and QD=4, the sheet gives 8.4 W on SATA and 8.7 W on SAS. That is one specific test, so do not subtract it from another maker's load figure without confirming the two tests match.

The table holds 1 Ultrastar 24TB rows, from £67.79/TB. A 24 TB SAS HC580 starts WUH722424AL52 and a 24 TB SAS HC590 starts WUH722624AL52, so compare the digits before AL to tell the generations apart. We run no separate 26 TB table on this page; any such row would fall into the new or used tables below. Other makers at this size belong to the wider 24 TB hard drive question.

WD Ultrastar prices on Amazon.co.uk: all new rows

This wider table shows 38 new rows at every capacity, sorted by pounds per TB inc VAT. HGST Ultrastar He10 leads at £26.61/TB, which is £266.13 for the drive. The data sheets on this page cover HC560 to HC590 only, and the table can also return other generations and HGST-branded Ultrastar rows, so some part numbers here may fall outside these figures. The Recording column prints a technology only where a document supports it.

Refurbished Ultrastar drives: the used rows

Anyone looking for refurbished Ultrastar hard drives should start here: 21 rows held as used on Amazon.co.uk, from £22.50/TB. Used is as much as this table states. We have not opened a WD document on recertified drives, so we say nothing about how such a unit is prepared, or whether WD's limited warranty reaches it.

What does apply is the seller's own duty. GOV.UK's guidance says a seller must offer a full refund if an item is faulty, not as described or does not do what it is supposed to. That is separate from any manufacturer's warranty, and refurbished enterprise hard drives raise the same distinction whichever maker is on the label.