WD Ultrastar DC HC570 22TB: Ten Disks, ArmorCache and the Part Numbers

WD Ultrastar DC HC570 22TB: what the extra disk buys

WD reaches 22 TB here by adding a platter, not by packing each one tighter. The sheet extends its 2.2 TB per disk to a new ten-disk platform in CMR format, and areal density actually sits lower than on the nine-disk HC560: 1109 Gbits per square inch against 1131. WD calls this the second-generation OptiNAND platform and an eighth-generation HelioSeal design.

Our reference for all of it is one document, dated August 2022, numbered D018-000537-AA01. It covers a 7200 RPM drive in the standard 3.5-inch form factor, with SATA 6Gb/s and SAS 12Gb/s versions. The sheet is Western Digital's, under the Ultrastar name; we have not read a document putting HGST on this model.

WD Ultrastar DC HC570 0F48155 and the other part numbers

Four combinations exist, so this grid is short. SATA SE means the Base SE SATA row: 0F48155. The sheet lists models and part numbers separately, so we paired all four using WD's key, where a final 1 is SED and a final 4 is Base SE, and the labels on the part numbers.

Sector format does not narrow the choice, since both interfaces list 4Kn at 4096 and 512e at 512. The decision comes down to the connector your system takes and whether you need self-encryption, so check both against your own controller's documents. We make no claim here about any particular server or NAS.

ArmorCache on the HC570: what WD says it changes

ArmorCache is the feature this sheet puts forward beside OptiNAND. WD says OptiNAND enables it, and that it combines the performance of write cache enabled mode with the data protection of write cache disabled mode, specifically for an emergency power off. The sheet rates random write at 4KB QD32 at 565 IOPS with write cache on and 565 with it off. That pair alone does not demonstrate the feature: the HC560's BL and SAS models show the same 565/565, and their sheet does not name ArmorCache.

The protection claim is WD's description, and we hold no independent power-loss test of this drive. Any buyer who has so far run write cache disabled for safety has reason to look at this feature, but the claim should be tested in your own environment before a production policy changes.

Ultrastar DC HC570 power and performance ratings

This sheet gives both interfaces a load figure from one named workload, so the 0.3 W gap can fairly be read across the row. WD's 22.44 PB rack claim assumes 42U, ten 4U JBODs and 102 drives per chassis, which is 1,020 drives.

• Sustained transfer: 291 MB/s (277 MiB/s) maximum, which puts a full 22 TB write at no less than about 21 hours, by our arithmetic.
• Random read: 212 IOPS at 4KB QD32.
• Random 50/50 read/write: 220 IOPS at QD4.
• Data buffer: 512 MB, with a portion for firmware. Latency: 4.16 ms.
• Designed for workloads up to 550 TB per year.
• Projected MTBF of 2.5 million hours and AFR of 0.35%.
• Limited warranty: 5 years. For UK terms on this model, we have not found a WD document.

How the Ultrastar DC HC570 differs from the HC560

Speed and workload do not move. Physical limits do, and not all in one direction.

Two results go against instinct. The drive with one more disk is 20 g lighter, and it gives up 10 G of operating shock rating. A rating is not a field result, so we would not read the lower number as proof of a weaker drive, though it is worth noting if your chassis or handling is rough. For the 20 TB side, including its AL and BL variants, go to the Ultrastar DC HC560 part-number grids. The WD Ultrastar overview takes in later generations.

Ultrastar DC HC570 listings on Amazon.co.uk

The table takes Amazon.co.uk listings whose title names the HC570, the WUH722222 prefix or one of the four short codes, and holds 1 listing right now. The price column is pounds sterling inc VAT, and the freshness line records when it was read.

A row's number is the thing to verify. Hold it against the four model numbers and four short codes above: a SATA row and a SAS row are different models, and a seller's title wording is not a WD document. The Recording column shows a technology only when a document ties it to that part number.

In-stock alternatives

None of these is the product this page covers: they are what is in stock on Amazon.co.uk beside it right now. Each row says why it is listed. Check the interface, form factor and part number against your system before buying.