128KB Sequential Read And Write
To read more on our test methodology visit How We Test Enterprise HDDs, which explains how to interpret our charts. We cover 128KB sequential performance measurements on page three, latency measurements on page five and power measurements on page six.
Sequential workload performance is one of the most important tests for nearline-class HDDs, because it can be indicative of large file transfers or RAID rebuild speed. We start the regimen by writing the entire surface of each drive from the beginning of the LBA range to the end, which represents a continuous stream of data that fills the entire drive. The performance steadily declines as the drive writes move from the edge of the platter (left) to the interior portions of the platter (right). The performance will decline until the workload returns to the outer edge of the platter, indicated by the large performance spike at the end of the test.
The Seagate 10TB writes the entire surface of its platters in approximately 14 hours, while the HGST He10 requires 30 min more to complete the same test. The WD Gold 8TB and the HGST He8 display different performance profiles, which is somewhat surprising because they are so similar during random workloads. The Seagate 8TB drive writes its full LBA range faster than the competing HDDs.
The HGST He10 leads the pack during the 128K sequential write test, but it suffers another performance decline during the QD128 and QD256 sections of the test. In contrast, the Seagate continues to offer a steady level of performance under heavier loads. The Seagate 8TB is impressive with sequential write workloads; it handily beats the HGST and WD 8TB competitors.
The Seagate 10TB and 8TB provide the highest overall performance during the heavier portions of the workload, and we can observe the HGST's performance reduction under heavy load in the latency over IOPS and QoS test results. However, it provides a tangible advantage during light QD1 workloads.
The Seagate 10TB draws the least power, but if the SATA version of the He10 lives up to HGST's specifications, it would easily consume much less power during this workload. The SAS variant remains impressive, and even manages to beat the SATA Seagate 8TB by a large margin, and falls into the competitive range of the other 8TB helium models.
The HGST He10 provides the best performance profile during the entirety of the workload, while the WD Gold and the He8 continue to provide nearly identical performance characteristics. The HGST He10 leads in nearly every metric during the measurement window, though the Seagate 10TB challenges it in the QD32 QoS breakout chart.
Mixed sequential workloads are important for nearline-class drives because in many cases there will be simultaneous read and write requests with large sequential data. Most workloads will likely skew towards the read-centric side of the plot, such as 90/10 to 70/30 read/write mixtures. The HGST He10 delivers a much better performance profile than the competing devices in the read-centric portions of the test, and it also has less variability. The He10 also provides the best QoS profile during the test, which cements its overall leadership position with sequential data.