R20GG: Dell 18TB 3.5″ 7.2K SAS HDD WUH721818AL5200

The Dell part number R20GG is an 18TB 3.5-inch 7.2K rpm hard drive with 512e sectors, supported in MD14xx storage enclosures. It is made by WD as model WUH721818AL5200, carries firmware US09 and is not self-encrypting.

WUH721818AL5200 is the 18TB SAS member of the Ultrastar DC HC550 family. The interface is SAS 12Gb/s with a 1200 MB/s maximum transfer rate, the platters spin at 7200 rpm and the data buffer is 512 MB. Average latency is 4.16 ms, and the sustained transfer rate reaches 269 MB/s on the 18TB capacity.

The drive is a helium-filled design (HelioSeal, sixth generation) with nine disks, CMR recording, energy-assisted magnetic recording and a triple stage actuator. Sector sizes of 512, 520 and 528 bytes are available in the 512e SAS configuration, and the 5200 ending of the model number marks 512e SAS with Power Disable pin 3 support and Instant Secure Erase.

Reliability figures are a projected MTBF of 2.5 million hours, a projected 0.35% annualized failure rate, one non-recoverable error per 10^15 bits read and 600,000 load/unload cycles. The workload rating is up to 550 TB per year with 24x7 availability.

Power draw is 8.8 W operating and 5.8 W idle. The 3.5-inch body is 26.1 mm high and 101.6 x 147 mm in footprint, weighs 690 g at most and tolerates 50 G operating shock. The Dell 10TB 512e SAS drive 07FPR is a related 3.5-inch 12G SAS option.