On the QNAP TS-259 Pro+, results were flat across the board, with 30 W pulled by all drives under stress. But on other devices, the difference between the lowest consumption (generally the 2 TB WD Red) to the highest – the Seagate NAS 4 TB ranged from 6% up to a huge 31% increase. Now, in real terms, were talking single digit wattage increases here so the electrical dials aren’t going to exactly fly off the meter – but the trend on power consumption was clear.
On read/write, results were more closely aligned. Read performance showed slight (low single digit percentage) differences for the Seagate drive on some devices, and either WD drive on others. With regard to write performance, you could see a slight improvement in speeds with the WD Red drives over the Seagate NAS drives, but again the difference ranges between 2 and 5% – barely noticeable on a dat to day basis.
So, a surprising result with regard to power consumption differences between Seagate and Western Digital NAS drives, but otherwise, you can take your pick and expect to see a similar file transfer performance on your NAS or home server.
The most expensive drives in our round up are the Enterprise hard drives. As a general rule, these drives are designed to be more durable than consumer drives. They’re intended for datacenter, cloud storage and other business needs and ship with features to enhance reliability – some of which have dripped down into the NAS drive category.
Western Digital’s WD Re is one such drive. We have included the 2 TB in our test, which is rated with an MTBF of up to 1.4 million hours. It includes the Dual Actuator technology we encountered on the WD Red NAS drives as well as an enhanced vibration cancellation feature known as Rotary Acceleration Feed Forward (RAFF). This monitors and corrects both linear and rotational vibration in real time, ensuring improved performance in multi-bay devices where vibration can be an issue. A third feature, StableTrac, is deployed in WD Re drives (greater than 2 TB) to further dampen vibration from the hardware around the drive. In these drives, the motor shaft is secured at both ends, stablising the disk platters and ensuring accurate tracking during read/write operations.
Add a multi-axis shock sensor to detect any impact on the drive, protecting the data on board, the same error recovery controls for RAID arrays we met with WD Red, NoTouch Ramp Load technology (see WD Green above) plus the ability to dynamically adjust the read/write head’s fly height in real time and you have a hard drive that’s loaded with features. On the flipside, the WD Re drive is going to cost you more than a consumer desktop or NAS drive, ships in lower capacities and, as a general rule, is likely to run hotter due to faster rotation speeds.
Joining the WD Re is the WD Se enterprise drive. Western Digital position this drive at a range of business uses, from SMB to high-end NAS and large-scale datacenter replication environments. Like it’s WD Re cousin, it includes Rotary Acceleration Feed Forward (RAFF) and the dual actuator feature seen on other WD drives as well as StableTrac. Indeed, a feature comparison with the Re drive shows there’s very little difference between the two models. Dig into the specification sheets, however, and you’ll see that the lifespan of the Se is expected to be shorter than the Re – just 1.2 million hours mean time before failure (MTBF) against the Re’s quoted 1.4 million hour figure.
Like the NAS drives, on face value it would appears that the WD Re and Se drives are similar in terms of features, and one would expect that to translate into similar performance, with long-term reliability the key differentiator. Well, if you check back in our specification table, you’ll see that the WD Re drives I’m testing spin more slowly than the Se drives – 5400 RPM vs 7200 RPM and that translates into lower power consumption. (Newer WD Re drives now also spin at 7200 RPM so this difference is likely to be less pronounced with the latest drives). The size of difference varies by device, but the trend is definitely there, with a 4% saving on the Windows 8.1 machine (19W with the WD Re drives vs 23 W using WD Se) all the way to a 20% reduction on the QNAP HS-251 Silent NAS (20W vs 25W).
Interestingly, differences in read/write performance were less pronounced. Aside from a strange case with the WD MyCloud Mirror which had a terrible time trying to read off the WD Re disk, read performance differences between the two drive models were within 5% – with the WD Re actually beating the WD Se read speeds on the ASUSTOR AS-304T and AS-609RS and QNAP TS-451. Similarly, write performance results were close and mixed with first place switching between the WD Re and Se models depending on the test device.
In conclusion, this class of devices, there’s a performance improvement to be gained in using older WD Re drives over WD Se with regard to power consumption but no real trend when it comes to file transfers.
Comparing Drive Classes
So, let’s recap on what we’ve learned so far. Firstly, hard drives contribute to the overall, absolute performance of your home server or NAS but they’re a lot less influential than processor, RAM and other entries on the spec sheet. Within each class of drive we’ve tested, there are some trends to pick out – certainly in the area of power consumption but less so when it comes to file transfer performance.
But which class of drive should you select for your home server or NAS? Let’s compare classes, and first take a quick look at pricing. As you’d expect, as features and average lifespan increases from class to class, so to does the retail price! I quickly pulled together a comparison of prices to show the difference you’ll pay today for a 3 TB capacity drive across Standard, Green, NAS and Enterprise drives at Newegg.com today.
That’s 3 TB of storage that could cost you anything from $105 for the Seagate Desktop drive to almost double for the Western Digital WD Re equivalent at $210. Suddenly, the price/performance ratio becomes much more important!
If we average the results from each class of drive we tested, we see there’s not a lot to differentiate each class in terms of performance. Enterprise drives are likely to consume more power than NAS and Desktop equivalents, but transfer performance across the classes will be broadly similar.
Sure, there’ll be variations at the drive and device level – get lucky and you’ll hit the sweet spot with a great drive and server combo. But as general rule, you should think more about the specific features I’ve outlined earlier for each class of drive when selecting your hard drives, than wondering which will be fastest or consume the least power on your specific server.
The value you attach to those features will ultimately determine your value for money perception – those Enterprise class drives are quoted with higher MTBF times – 1.4 or 1.2 million hours plays 1 million for a WD Red NAS drive. Is that reliability worth $80 – $90 a drive? Amortised over the suggested 45 years of additional life you’d get out of that Enterprise drive, the additional cost is negligible – that is, if you own the drive that long!
Certainly, the error recovery controls built into NAS-class and Enterprise drives are worth the premium, from an uptime and convenience standpoint – that’s just a $20 premium on top of a standard desktop drive if you opt for a NAS hard drive instead. The data protection features found in NAS drives, designed to minimise data corruption in the event of an unexpected power loss are also well worth that premium – anything you can do to protect the data on your drives at a reasonable price is worth picking up.
So, based on our tests and a thorough review of the features available across the array of hard drives available today, NAS drives most definitely offer the most relevant blend of features, performance at a sensible price. With performance broadly similar across Seagate and Western Digital today, but with an advantage on power consumption and capacity, then Western Digital’s WD Red drives are my 2014 recommendation for home server and consumer NAS owners. They’ll be the drives we’ll be installing in all of the NAS devices we review for the foreseeable future.
Of course, once thing you can be sure of is that the storage industry isn’t finished innovating. New technologies, higher capacities and enhanced features are always just around the corner, so stay tuned to WGS as we bring you news of the latest advances as they arrive.