by Hugh Barros
10/13/2013 | 10:05 AM
Following Western Digital's example, Seagate has introduced a special series of hard disk drives optimized for entry-level and midrange network attached storage devices. These are home and SMB-oriented NASes that can accommodate one to five HDDs. Seagate seems to be optimistic about the NAS market as users switch from desktop PCs to mobile devices while the amounts of data, especially multimedia data, get larger and larger. There are certain specifics to using HDDs in a NAS such as nonstop operation, installation of several HDDs into a single case, RAID configurations.
Unfortunately, quite a lot of technical parameters are hard to evaluate in practice, especially when it comes to market positioning and optimizations. Seagate talks about 24/7 operation and NASWorks technology which is targeted at typical NAS applications by making the HDD more efficient in fault-tolerant RAIDs (the time for data recovery attempts by the HDD’s own means is reduced), lowering vibrations and featuring a power management system. On the other hand, Seagate says that its desktop HDDs can be used for NASes as well.
The new series consists of three models with capacities of 2, 3 and 4 terabytes (ST2000VN000, ST3000VN000, and ST4000VN000), so Seagate can claim that its NAS-optimized HDDs are 30% larger than competitor products. Indeed, Western Digital's Red series doesn't yet include 4TB models. Still, there are several 4-terabyte HDD models available on the market, which are perfectly compatible with NASes.
The new models all share a few common traits: SATA 6 Gbit/s interface, 64MB cache, power consumption of less than 5 watts at work and 0.5 watts in standby mode, noise level of 25 dB or lower, 70°C max temperature of the drive case, 600,000 heads load/unload cycles, MTBF of 1,000,000 hours, and up to 1 year of power-on hours. Interestingly, some of these numbers coincide with the WD Red’s (load/unload, MTBF, temperature). The series comes with a 3-year warranty, which is 1 year longer than the desktop series. Seagate only offers a 5-year warranty for some of its enterprise product series.
Talking about the warranty, Seagate’s website offers a simple form for you to type in your HDD's serial number, model name and region to learn when its warranty period expires. On the other hand, if you are choosing a new HDD, it is next to impossible to know its warranty term. Moreover, the warranty may vary depending on your HDD acquisition method (e.g. a part of a desktop PC or a third-party NAS).
It is generally recommended to check out the NAS maker's compatibility list when choosing HDDs for your NAS. Of course, it may be possible to use models not listed there, but there's no reason to run the risk of incompatibility. Seagate is good from this aspect. Almost immediately after the introduction of the new HDD series Seagate announced its compatibility with products from all the leading NAS makers including ASUS, LaCie, QNAP, Synology and Thecus. It must be noted, however, that the new HDDs are not on some of the compatibility lists as of the time of our writing this review.
It must be mentioned that Seagate also offers Constellation CS and Constellation ES.3 drives. They feature additional technologies that make them perfect for large storage systems.
Performance, power consumption and temperature are the parameters of NASes that we can test in our labs. Noise might also be measured, yet it is not clear how the test conditions should be organized since measuring the noise produced by a single HDD wouldn't be useful in practical terms. Subjectively, the new HDDs are rather quiet for a home environment but much will depend on the NAS design and its cooling system.
Seagate’s new series is represented by the highest-capacity model ST4000VN000. We will compare it with 2TB WD20EFRX drives because we can’t take one same-capacity WD drive for this test. Anyway, we guess the more important factor is that the WD Red series was introduced about a year ago, so the newer HDDs should have progressed since then.
We will benchmark performance using an x86-based ASUSTOR AS-604T NAS with firmware 1.0.9.R4U1. The client PC is based on an Intel Core i5 and Windows 8. It is connected to the NAS directly via an Intel Gigabit Ethernet controller. Jumbo Frames are enabled.
We adjusted the standard templates of Intel NASPT for our tests by increasing the file size to 8 GB for sequential operations. We also added random read and write templates. When analyzing the results, we should remember that NAS usage scenarios differ between users. It is impossible to compare different NASes since their HDDs and firmware may vary greatly.
The first diagram shows the performance of single-disk configurations. It is a typical scenario for home NASes when data security is ensured by means of backups.
The new HDD is 80 and 100 MB/s fast at reading and writing, respectively. The Seagate is slower than its opponent by 10% or more at reading, reading+writing, content creation, photo album processing and random writing. It enjoys the largest advantage (9%) in the random reading test. The random writing scenario is hardly popular for home NASes because they are usually used for sequential writing (writing a large video file, a backup copy, etc).
The second configuration is a striped array which ensures higher performance but not fault-tolerance. Home users may prefer it to get higher speed and to combine several HDDs into a single disk volume. Data security is ensured through additional methods then.
The top speeds are higher indeed: up to 100 and 120 MB/s at reading and writing, respectively. The HDDs are close to each other at sequential operations, differing by less than 5%. The Seagate is only 20% ahead at single-threaded reading. On the other hand, the Seagate slows down when it has to read multiple data threads whereas the WD accelerates. As for random-address operations, the Seagate is faster at reading but slower at writing.
Modern HDDs are generally reliable products and fault tolerance is not among key priorities for entry-level NASes. That's why RAID5 configurations can but seldom be seen in home NASes. However, they are quite appropriate for SMBs. Let’s check this out.
RAID5 isn't difficult for modern NASes based on the x86 platform. The Seagate HDDs deliver nearly the same performance as in the striped array. They are ahead of the WD drives at sequential operations (except for dual-threaded reading). As for random-address operations, the Seagate solution is faster at reading and slower at writing.
RAID6 is hardly ever used for 4-bay NASes but it is the heaviest mode for the NAS’s processor, so we want to check it out as well.
The Seagate drives have a clear advantage at sequential operations here. As opposed to the WD drives, they don’t slow down much when reading in the RAID6 configuration. The speed of random operations is comparable to that of the previous configurations.
Summing up our performance tests, we can say that the new Seagate NAS series is comparable to or better than Western Digital's Red series. The two series differ the most at random-address reading and writing. Considering that random writing isn’t a popular usage scenario for entry-level NASes which are used for storing, sharing and backing up files, the Seagate NAS seems to be the more preferable solution.
We measure the power consumption of our HDDs on a special testbed that can connect to the 5V and 12V rails. So, the results reflect the requirements of the HDDs under different usage scenarios without counting in the power draw of the NAS’s hardware platform. The random/sequential read and write loads are created with the IOMeter software. When analyzing the results, do not forget that the HDDs differ in storage capacity.
The Seagate NAS series is 15% and more economical in idle mode and at random reading. It is also better by 6% at random writing. But when it comes to sequential operations, which require fewer movements of the read/write heads, the new series needs 10% more power than their opponents. This is still a good result considering the twice larger storage capacity. The peak power draw is less than 5.5 watts, so the power supplies and cooling systems of modern NASes should easily cope with the new HDDs. As for the startup current, the Seagate NAS is better than the WD Red as the last diagram shows.
Most NASes regulate the speed of their cooling fan automatically, so it would be incorrect to compare the HDDs here. Anyway, their temperature was no higher than 43°C in RAID5 during our tests. The system sensor reported 55°C and the processor was as hot as 75°C. So, the new models are okay in this respect.
It is good that we can have new HDDs optimized specifically for entry-level NASes. NAS applications have their peculiarities indeed whereas users have been getting more interested in entry-level NASes due to the transition from desktop PCs, which can accommodate several HDDs, to compact notebooks and tablets.
Seagate’s NAS-optimized HDD series may come in handy for such applications. Although the company’s other products may be used in NASes as well, the new series would be a better choice. The STx000VN000 models are already on the compatibility lists of the major NAS manufacturers. Many of their specs coincide with those of Western Digital’s Red series, but Seagate offers maximum storage capacity. If you want a NAS-optimized 4-terabyte drive, there is no other option available today.
When it comes to performance, it is the platform rather than the hard disks that determine the speed of an entry-level NAS. We have tested one of the fastest x86-based 4-bay NASes with Seagate’s new HDDs and its performance is limited by the Gigabit Ethernet interface. Seagate’s HDDs have proved to be generally superior to their WD Red opponents. The differences between them are especially conspicuous at random operations where the Seagate drives were better at reading and worse at writing. The new HDDs are also better in RAID6 configurations when doing sequential reading. Having newer components, they are superior in such parameters as power consumption and temperature, too.
Reliability is one of the most important parameters for any HDD, but we can’t evaluate it in our tests. Judging by the specified MTBF and the warranty period, the new series should be at least as reliable as the older drives.
As for the price factor, the NAS-optimized products from Seagate are considerably more expensive than their regular desktop counterparts and a little more expensive than their WD opponents. It must be due to their being new products rather than to any technical issues.
Thus, if you need fast, cool and quiet large-capacity HDDs for an entry-level NAS, the Seagate NAS series is going to be the perfect option.