The amount of data in the world is endlessly multiplying, heading towards a projected 40 trillion gigabytes by 2020, but IT budgets are not increasing at such a rapid clip. Seagate's release of their 6TB nearline Enterprise Capacity 3.5 HDD v4 addresses the need for more capacity in the datacenter. Comparisons to the only other available 6TB drive, the HGST Ultrastar He6, are unavoidable. While HGST only extends the benefits of their helium-infused He6 to the 6TB capacity, Seagate has brought an entire family of 7,200 RPM drives in capacities of 6, 5, 4, and 2TB in the familiar 3.5-inch form factor. The v4 features either a dual-port 12GB/s connection or SATA 6Gb/s.
Seagate took an evolutionary tack with their eighth generation platform, while HGST went with a revolutionary new design that relies heavily upon the advantages of helium. Seagate utilizes standard PMR and increased areal density to deliver the 50 percent capacity boost. Areal density jumps 25 percent to 643 Gbits/square-inch, and the new Advanced Format 4KN format helps provide an increase to 1000GB per platter.
The combination of industry-leading areal density and ingenious design leads to a rather conventional approach to capacity expansion. Several architectural design modifications enable the addition of a sixth platter, one fewer than the HGST drive. Seagate added another inertia actuator to reduce coil size and reduced the thickness of the base plate. Adding two more heads required a novel approach to combat turbulence-induced head flutter and vibration. Seagate employed a top disk separator plate to improve airflow, a less radical design than the helium in the HGST design.
One of the immediate concerns with larger capacity HDDs are RAID rebuild times. These can stretch into days with current 4TB drives. This has led to the exploration of new approaches, such as object storage, to remove the requirement for RAID. The Seagate v4 has RAID Rebuild functionality built-in. RAID Rebuild, part of the SAS standard, allows communication between the drive and a RAID controller to perform targeted rebuilds. These surgical rebuilds can remove the requirement for rebuilding an entire array. This technology is offered on some previous-generation Seagate HDDs, but widespread support from RAID controller vendors is just now becoming a reality. The Seagate Enterprise Capacity v4 is also faster than its 6TB competitor, which significantly reduces rebuild time.
The Seagate v4 supports Super Parity, which adds an extra parity bit to improve data integrity for data at rest. In conjunction with enhanced error correction, the v4 features a standard error rate of 1 per 10^15. The v4's MTBF is 1.4 million hours, and it has an AFR of 0.63 percent while handling nearline workloads of 550TB.
The HGST He6 drastically reduces power consumption by leveraging low-resistance helium to enable thinner, lighter platters. The Seagate v4 build is heftier at 780g due to the increased number of standard-sized platters. The primary difference between the Seagate and HGST offerings are performance and power consumption. Seagate's customer feedback has emphasized a priority for performance over power consumption. The Seagate v4 has higher power draw than its competitor, but it has made significant efficiency gains.
The typical operating power of the Seagate v4 is 11.27W, the same as their previous generation Constellation ES.3. This Seagate v4 exhibits a marked improvement of 1.87W-per-TB, compared to 2.81W-per-TB for the ES.3. The only slight increase over the ES.3 is idle power, which went from 6.73W to 6.9W. The HGST He6 is designed from the ground up for efficiency, even at the expense of performance. This leads to an admirable power consumption of 1.2W-per-TB (operating) and a low 3.7W idle power draw.
The maximum sustained transfer rate of the Seagate v4 is 216 MB/s, which is considerably faster than the He6's 177 MB/s. Another performance differentiator is the faster seek time of 4.16ms for the v4, and the Seagate v4 features a larger 128MB multi-segmented cache buffer.
The philosophies behind the two drives are drastically different even though they cater to the same market. The Seagate v4 looks to provide more storage within the existing power envelope and with increased performance. The HGST He6 unabashedly strives to lower ongoing power consumption to deliver enhanced TCO, even if performance remains on-par, or below, previous generation drives.
For months, we have relied upon both companies' word on the matter, so now let's dive in and see for ourselves.
PRICING: You can find the Seagate Enterprise Capacity 3.5 HDD v4 (6TB) for sale below. The prices listed are valid at the time of writing but can change at any time. Click the link to see the very latest pricing for the best deal.
United States: The Seagate Enterprise Capacity 3.5 HDD v4 (6TB) retails for $596.33 at Amazon.