Western Digital WUH721816ALE6L4 16TB 7200RPM SATA 6Gb/s 3.5in Ultrastar DC HC550 Hard Drive

The Western Digital WUH721816ALE6L4 is the 16TB SATA model of the Ultrastar DC HC550, also sold under WD part number 0F38462. It is a helium-sealed, 7200 RPM, 3.5-inch data center drive with a 512MB buffer. WD builds the HC550 on a nine-disk platform and uses conventional magnetic recording (CMR), so it drops into existing RAID, NAS and software-defined storage designs without the write-pattern limits of shingled drives.

WD rates the 16TB SATA model for a sustained transfer rate of up to 262 MB/s, workloads of up to 550TB per year and a projected MTBF of 2.5 million hours. Typical uses are bulk and nearline tiers: backup and archive pools, object storage such as Ceph, Hadoop data nodes and capacity shelves behind a faster SSD or 10K SAS tier. It is a cost-per-terabyte drive, not a low-latency one.

The model number tells you the configuration. E6 means a 512e SATA 6Gb/s interface, L means the legacy pin 3 layout with no Power Disable feature, and the final 4 means the Base (SE) security level: no encryption, with sanitize overwrite for drive retirement. If you need a self-encrypting drive, WD's SED version is WUH721816ALE6L1. If you need dual-port SAS, look at the SAS models of the HC550 instead.

What to check before ordering:

• This is a bare drive. Hot-swap bays in servers and NAS units need a tray, and HPE or Dell servers need their OEM carrier and may flag non-OEM firmware.
• The legacy pin 3 layout suits older backplanes and power supplies that feed 3.3V on that pin.
• 512e presents 512-byte logical sectors on 4K physical sectors, which works with current operating systems and hypervisors.
• Match capacity, interface and sector format to the other drives in the same RAID group.