Western Digital WUH722222ALE6L4 22TB 7200RPM SATA 6Gb/s 3.5in Ultrastar DC HC570 Hard Drive

The Western Digital WUH722222ALE6L4, WD part number 0F48155, is the 22TB SATA model of the Ultrastar DC HC570. WD moved to a ten-disk, helium-sealed platform for this drive and kept conventional magnetic recording (CMR), so you get 22TB in a standard 3.5-inch bay without shingled recording. It spins at 7200 RPM and has a 512MB buffer.

The HC570 uses WD's OptiNAND design, an embedded flash device that stores drive metadata. One practical result is ArmorCache: WD states that data held in the drive's write cache is saved if power is lost suddenly, whether the write cache is enabled or disabled, and that performance is the same in both modes. For capacity arrays that have to choose between speed and write-cache safety, that removes a trade-off.

WD's data sheet lists a sustained transfer rate of up to 291 MB/s, a workload rating of up to 550TB per year, a projected MTBF of 2.5 million hours and 5.7W at idle. The drive suits dense nearline storage such as object stores, backup and archive tiers, scale-out file systems and analytics data sets. Transaction-heavy workloads still call for 10K SAS drives or SSDs.

This model is 512e SATA 6Gb/s with the legacy pin 3 layout (no Power Disable) and Base (SE) security, so it does not encrypt. The SED version is WUH722222ALE6L1 and the SAS versions carry different model numbers. Before ordering, check:

• That your HBA, RAID controller or NAS supports 22TB drives on current firmware.
• That you have trays for a bare drive. HPE and Dell servers need OEM carriers and may flag non-OEM firmware.
• That every drive in a RAID group shares the same capacity and sector format.
• That your rebuild plan allows for the time a 22TB member takes to resync.