The Seagate Enterprise Performance 15K HDD v4 increases capacity to 600GB, and boasts solid gains in performance. Let's take a closer look at the drive.

Introduction

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The Seagate Enterprise Performance 15K HDD v4 brings an increase in capacity to the 2.5" 15K HDD segment. The 15K v4 offers capacities of 600GB, 450GB, and 300GB in the 2.5" form factor. Along with the bump in capacity, Seagate offers 228 MB/s in sequential performance, a 24% increase in the SDR (Sustained Data Rate) over competitive offerings. The 15K v4 also brings a 3% increase in random read performance, and a 4% jump in random write performance.

The increased speed of 15K HDDs makes them attractive for addressing Tier-1 application performance requirements. The 2.5" form factor works well for blade, rack, and tower servers hosting transaction-based applications, and addresses increasing demands for more performance and capacity in a smaller space. The 15K v4 offers many of the inherent advantages of the 2.5" form factor, such as lower power consumption and higher performance, in comparison to the 3.5" 15K HDDs.

One of the newest additions to the Seagate 15K line is the arrival of Turbo SSHD models. These hybrid models provide seamless workload acceleration without any user configuration or management. We recently took an in-depth look at the Seagate Turbo SSHD, and the inclusion of a 32GB layer of eMLC NAND cache delivers incredible performance benefits. The option to choose a standard 15K HDD, or a 15K SSHD with built-in caching, provides users the flexibility to tailor their deployments to application requirements.

The dual-port 6Gb/s connection offers high-availability features, such as multipath and failover, to the performance segment. The UBER rating of one per 10^16 is standard for this class of drive, but the 15K v4 differentiates itself with a robust two million hour MTBF. The drive also uses a larger 128MB multi-segmented cache to help boost performance.

There is an incremental increase in power consumption from the previous generation, but the doubling of capacity easily outweighs the small increase. The 15K v4 makes an impressive leap in watts-per-GB by doubling capacity at the cost of an additional .6 watts. The Enterprise Performance 15K v4 also touts an impressive 70% reduction in power in comparison to 3.5" 15K products. Power consumption equals heat, and Seagate dynamically reduces power consumption during operation with proprietary PowerTrim technology.

Performance-based deployments often require robust storage security features to meet data security and compliance initiatives. The 15K v4 covers the bases with SED, FIPS 140-2, and ISE versions. These versions protect data on the drive, and ease costs during the drive retirement, or repurposing process. The Enterprise Performance 15K HDD v4 also offers broad compatibility with 512N, 512E, and 4k format options available.

The 15K v4 line also offers thermal monitoring, a humidity sensor, and support for SAS-based Protection Information. Seagate has also focused on the Unified Storage Architecture, which uses fewer components to reduce failure points, and reduce design, qualification, and support costs.

The battle for high-performance slots has intensified as SSDs have brought stiff competition to the table, but this has also led to more competitive pricing and performance from the venerable 15K HDD segment. Let's take a closer look.

Enterprise Performance 15K HDD v4 Internals and Specifications

Enterprise Performance 15K HDD v4 Internals

The Enterprise Performance 15K HDD v4 comes in the 2.5" form factor.

A foam pad between the case and the PCB helps absorb vibration, and the drive controller and motor controller have thermal pads to shed heat into the case of the drive. There are angled accelerometers on the upper left, and lower right of the PCB. The Samsung DRAM chip occupies the middle of the PCB, and several capacitors are on the upper left.

The Marvell I 1062-B0 controller is flanked by the 128MB multi-segmented cache package. A SMOOTH motor controller is on the upper left.

The Enterprise Performance v4 utilizes a 6Gb/s SAS connection.

Idle power consumption is a pain point in the datacenter. The Seagate Enterprise Performance 15K HDD v4 utilizes PowerChoice Technology, Seagate's proprietary implementation of the T10/T13 Approved Standard. PowerChoice provides four enhanced idle modes that place the drive into deeper quasi-sleep cycles to conserve power. The feature is enabled with a SAS Mode Page, or SATA Set Feature command states triggered by the length of drive inactivity. There is also the option for immediate host-initiated power transitions in a typical implementation. Once enabled, PowerChoice places the drive into successively deeper idle states with SAS/SATA commands, but each consecutive sleep mode requires more time for resumption. We did not test with enhanced PowerChoice states enabled.

The Enterprise Performance 15K HDD v4 averages a seven watt power draw during the idle power state. It is important to note this measurement is without PowerChoice technology activated; the drive can idle lower when using PowerChoice. The 450GB 15K v4 features more capacity than the 147GB and 300GB competitors do; on an idle watts-per-GB basis the 15K v4 offers very competitive idle power consumption metrics.

Enterprise Performance 15K HDD v4 Specifications

The 12Gb/s Seagate Enterprise Performance 15K HDD v4 HDD we are testing today is the 512e variant with the ST450MP0004 part number. There are 4K, 512n, SED, and FIPS variants available with varying part numbers.

Test System and Methodology

Our approach to storage testing targets long-term performance with a high level of granularity. Many testing methods record peak and average measurements during the test period. These average values give a basic understanding of performance, but fall short in providing the clearest view possible of I/O QoS (Quality of Service).

While under load, all storage solutions deliver variable levels of performance. "Average" results do little to indicate performance variability experienced during actual deployment. The degree of variability is especially pertinent, as many applications can hang or lag as they wait for I/O requests to complete. While this fluctuation is normal, the degree of variability is what separates enterprise storage solutions from typical client-side hardware.

Providing ongoing measurements from our workloads with one-second reporting intervals illustrates product differentiation in relation to I/O QoS. Scatter charts give readers a basic understanding of I/O latency distribution without directly observing numerous graphs. This testing methodology illustrates performance variability, and includes average measurements, during the measurement window.

IOPS data that ignores latency is useless. Consistent latency is the goal of every storage solution, and measurements such as Maximum Latency only illuminate the single longest I/O received during testing. This can be misleading, as a single "outlying I/O" can skew the view of an otherwise superb solution. Standard Deviation measurements consider latency distribution, but do not always effectively illustrate I/O distribution with enough granularity to provide a clear picture of system performance. We utilize high-granularity I/O latency charts to illuminate performance during our test runs.

We conduct our tests over the full LBA range to allow each HDD to highlight its average performance. All three HDDs spin at 15,000 RPM, and feature varying capacity points, which should be taken into consideration when analyzing performance and power metrics. The first page of results will provide the key to understanding and interpreting our test methodology.

Benchmarks - 4k Random Read/Write

4k Random Read/Write

Each level tested includes 300 data points (five minutes of one second reports) to illustrate performance variability. The line for each queue depth represents the average speed reported during the five-minute interval. 4K random speed measurements are an important metric when comparing drive performance, as the hardest type of file access for any storage solution to master is small-file random. 4K random performance is a heavily marketed figure, and is one of the most sought-after performance specifications.

The Enterprise Performance 15K v4 starts out with an impressive average of 543 IOPS at QD256, trailed slightly by the Savvio 15K.3 with 540 IOPS, and the Toshiba MK1401GRRB with 507 IOPS.

Our Latency vs IOPS charts compare the amount of performance attained from each solution at specific latency measurements. Many applications have specific latency requirements. These charts present relevant metrics in an easy to read manner for readers who are familiar with their application requirements. The HDDs that are lowest and furthest to the right exhibit the most desirable latency characteristics.

All three HDDs fall within a similar latency envelope, though the Savvio 15K.3 ekes out a slight win.

The Enterprise Performance 15K takes a big lead with an average of 506 IOPS at QD256. The Savvio 15K.3 drive averages 428 IOPS, and the Toshiba averages 444 IOPS.

The Enterprise Performance 15K v4 separates itself from the pack with a superb latency-vs-IOPS ratio.

Our write percentage testing illustrates the varying performance of each solution with mixed workloads. The 100% column to the right is a pure write workload of the 4k file size, and 0% represents a pure 4k read workload.

The 15K v4 separates itself from the pack as we mix in more write activity, and takes a considerable lead with pure random write activity.

We record power consumption measurements during our test run at QD256. It is important to consider watts-per-GB in the overall analysis due to the varying capacities in the test pool.

The Enterprise Performance 15K v4 requires 7.7 watts during the test.

We generate IOPS-to-watts measurements from data recorded during the test period. The 15K v4 averages 59 IOPS-per-watt during the write workload, and 69 IOPS-per-watt during read activity.

Benchmarks - 8k Random Read/Write

8k Random Read/Write

Server workloads rely heavily upon 8k performance, and we include this as a standard with each evaluation. Many of our server workloads also test 8k performance with various mixed read/write workloads.

The average 8k random read speed of the Enterprise Performance 15K v4 is 531 IOPS at QD256, and the Savvio 15K.3 takes a slight lead with 535 IOPS. The Toshiba 15K comes in third with 522 IOPS at QD256.

The Enterprise Performance 15K v4 runs neck and neck with the previous-generation Savvio 15K.3.

The Enterprise Performance 15K v4 delivers a big win with random write activity again with an average of 502 IOPS at QD256, and the Savvio 15K.3 provides 430 IOPS. The Toshiba averages 479 IOPS.

The stellar write performance from the 15K v4 yields an excellent latency-to-IOPS ratio.

The Enterprise Performance 15K v4 leverages its healthy random write performance in mixed workloads to win this test.

Power consumption for the 15K v4 averages 8.2 watts.

The 15K v4 provides 59 IOPS-per-watt with 8k write activity, and 68 IOPS-per-watt during read activity.

Benchmarks - 128k Sequential Read/Write

128k Sequential Read/Write

We write to every LBA to highlight performance degradation from the outer to inner tracks of the drive. The drives begin with much higher speed on the outer tracks, and lose speed as it works inward. The small platter sizes allow the drives to write the entire platter of the drive very quickly, and the varying capacity points in the test pool are clear, with the high-capacity Enterprise Performance 15K v4 taking the longest to complete a pass across the platter.

128k sequential speed reflects the maximum sequential throughput of the HDD, and is indicative of performance in OLAP, batch processing, streaming, content delivery applications, and backup scenarios. Today's HDDs are increasingly used for sequential workloads as SSDs encroach upon the application space.

The Enterprise Performance 15K v4 drive averages an impressive 252 MB/s during the sequential read workload at QD256. The Savvio 15K.3 averages 187 MB/s, and the Toshiba offers 198 MB/s.

The 15K v4 exhibits excellent latency characteristics with sequential read activity.

Sequential write performance is important in tasks such as caching, replication, HPC, and database logging. The Enterprise Performance 15K v4 averages 251 MB/s, the previous-gen Savvio 15K.3 averages 187 MB/s, and the Toshiba weighs in with 196 MB/s.

The only weakness of the 15K v4 is an odd latency distribution that occurs right at the beginning of a sustained heavy write workload. The drive levels off to normal performance once the workload is underway, and this may be due to some reordering of data during the initial burst of activity.

The mixed-workload sequential testing is one of our most demanding tests. Many drives will fare very well on the high-end, but fall short with mixed sequential activity. The Enterprise Performance 15K v4 delivers class-leading sequential performance across the board.

The 15K v4 averages 7.8 watts.

The Enterprise Performance 15K v4 averages 28 MB/s-per-watt for both read and write activity.

Benchmarks - Database/OLTP and File Server

Database/OLTP

This test consists of Database and On-Line Transaction Processing (OLTP) workloads. OLTP is the processing of transactions such as credit cards and high frequency trading in the financial sector. Databases are the bread and butter of many enterprise deployments. These demanding 8k random workloads with a 66 percent read and 33 percent write distribution bring even the best solutions down to earth.

The 15K v4 drive delivers an impressive 545 IOPS at QD256 during the OLTP workload. The Savvio 15K.3 averages 469 IOPS, and the Toshiba provides 532 IOPS. There is a massive improvement in the new 15K v4 over the previous-generation Savvio 15K.3.

Latency performance scales within expectations during the course of the workload, with the Enterprise Performance 15K v4 taking a lead in efficiency.

The 15K v4 requires an average of 7.82 watts during the transactional workload.

The Enterprise Performance provides 62 IOPS-per-watt.

File Server

The file server test consists of typical file server workloads. This profile tests a wide variety of file sizes simultaneously, with an 80% read and 20% write distribution.

The Enterprise Performance provides 526 IOPS at QD256, but the Savvio 15K.3 jumps out to a big lead with 688 IOPS. The Toshiba averages 519 IOPS.

The Enterprise Performance 15K v4 averages 8.05 watts during the fileserver workload.

The 15K v4 offers 64 IOPS-per-watt during the measurement window.

Benchmarks - Email Server

Email Server

The email server workload is a demanding 8K test with a 50% read and 50% write distribution. This application is indicative of the performance in heavy write workloads.

The Enterprise Performance 15K v4 leads the charts again with an average of 549 IOPS at QD256. The Toshiba comes in a close second with 510 IOPS, and the Savvio 15K.3 delivers 466 IOPS.

The Enterprise Performance 15K v4 delivers excellent latency during the measurement window.

The 15K v4 averages 7.8 watts during the email server workload.

The 15K v4 offers 64 IOPS-per-watt during the measurement window.

Final Thoughts

The need for nimble storage arrays with enough capacity for large datasets is increasing in the datacenter. Pairing fast drives with a small form factor and good power consumption characteristics delivers great performance at a reasonable price. The continuing focus on slimmer server form factors has given the 2.5" HDD segment a boost. The 15K HDD sector still has plenty of use in the datacenter despite continued pressure from SSD competitors, and Seagate has even broadened their line to include Turbo SSHD models (evaluated here) to boost performance.

The Enterprise Performance 15K HDD v4 is a good fit for those looking to boost application performance in blade servers, and space-constrained environments. The boost up to 600GB is a solid increase from previous-generation 15K offerings, and comes with a healthy increase in speed. Performance HDDs are increasingly used in complimentary roles to flash storage, and many caching and tiering algorithms pass sequential data down to the HDD tier. This reduces flash wear and leverages HDDs' inherently robust sequential performance.

The Enterprise Performance 15K v4 took a big lead in both sequential read and write workloads by a large margin in our testing. Incremental performance increases are expected as technology progresses from generation to generation, but the 15K v4 impressed us with a huge leap in sequential performance. The performance gains were also pronounced in mixed sequential workloads, and the 15K v4 took a commanding lead in our mixed sequential workload testing.

Random workload performance was also impressive with a continuation of the solid random read of the previous generation Savvio 15K.3, and a big jump in random write metrics. The Enterprise Performance 15K v4 regularly outpaced its competitors in both 4k and 8k random write performance, and this was very apparent in our mixed random workload testing. The 15K v4 distanced itself from the competition as we mixed in more random write activity. This enhanced random write speed also came with a big reduction in overall latency.

The 15K v4 also fared well in our server workload testing, with good performance in OLTP workloads. The write-centric email server workload was also a particular strength for the 15K v4. The only hiccup in performance came with the fileserver workload, where the previous-generation Savvio 15K.3 took a commanding lead.

The increase in capacity also came with an expected increase in active and idle power consumption. When viewed from a watts-per-GB perspective, the 15K v4 remains competitive with other high-speed offerings, and offers double the capacity with a slight 0.6 watt increase in comparison to the previous generation. The drives also offer a massive 70% reduction in power consumption as compared to 3.5" 15K HDDs.

The Enterprise Performance 15K v4 brings enhanced capacity to the 15K segment, and a spate of enterprise-class features, such as support for Protection Information, RAID Rebuild, thermal monitoring, and a two million hour MTBF. The 6Gb/s SAS connection is a good fit for the high performance segment with its high-availability features, and SED and FIPS options are available for the security conscious. The Seagate Enterprise Performance 15K HDD v4 wins the TweakTown Best Performance Award for the 2.5" 15K segment.