Which Hard Drive is Best for Your Home Server or NAS?

Those features include IntelliSeek – what’s that you say? Well, in older hard drives, the drive head would move rapidly to the point on the drive where the next data is due to be read or written and then have to wait for the disk platter to spin around to the correct sector. Once the data was read or written, off goes the actuator to the next point and again it would sit and wait for the disk to spin to the correct location. That repeated process would lead to additional disk vibration and power consumption. Intelliseek solves that problem by more accurate timing of the actuator movement, so it reaches the right point on the disk just as the platter is rotated to the correct position. Better orchestration of movement equates to less vibration and lower power consumption. So that delivers some of the WD Green drive’s low power credentials.

Western-Digital-2TB-Green-WD20EARX-HDD

Another feature you’ll hear mentioned regularly on modern hard drives is “Advanced Format” or “Advanced 4K Format“. This refers to the size of the disk sector, which historically was 512 bytes, but in modern “advanced format” drives produced after 2010 is 4096 bytes. This standard is now adopted across the industry and is supported by all modern devices and operating systems – however, wind the clock back a couple of years, and there were compatibility headaches. Why should you care about Advanced Format? Well, you probably shouldn’t as it’s no longer big news, but it’s an important technology progression that improved storage efficiency greatly – allowing manufacturers to cram more storage space on to those platters.

WD Green drives also benefit from a feature called a Dual Stage Actuator. Drives with this feature include a drive arm (which moves the read/write head) with two joints, rather than the usual one. The benefit? More precise movement of the head delivers greater positional accuracy over the data tracks, leading to improved performance. Dual Stage Actuators were traditionally offered in expensive enterprise drives, but in recent years have found their way into certain consumer drives too.

Here’s another crazy feature name from Western Digital – NoTouch Ramp Load Technology. According to WD, in drives that include this feature, a plastic ramp secures the actuator in a specific position so that the heads always stay suspended in the air and never actually touch the platters surface. No touch translates into less wear and tear, and improved reliability. So there!

All of these power-efficient features sound fabulous – but will they impact performance?

NAS Hard Drive Benchmarks: Desktop Hard Drive Results

In my tests, I uncovered a few insights that I’ll share. Firstly, and this may come as no surprise to many, the absolute performance of your NAS or home server – expressed here in network file transfer rates or power consumption – depends more heavily on the processor, RAM and other hardware used in the device than the hard drives you select. Low specification hardware will not suddenly be transformed by slipping in a different hard drive, and neither will high specification hardware be compromised too greatly by using a green desktop drive over a standard drive or vice versa.

To use a car analogy, switch from standard tyres to racing tyres on your Ford Focus, and you’re still not going to beat that Ferrari in a straight line race. But you may go a little quicker than you would if you hadn’t changed them.

The Green drives did indeed deliver lower power consumption than standard desktop drives when compared at the device level – although again, the server hardware itself contributes greatly to the result. For example, the WD MyCloud Mirror pulls just 15 W under load using WD Blue 1 TB hard drives, while our Windows 8.1 machine needed 42 W with a 2 TB Green Drive array. However, switch from the hungriest standard desktop drive to a power sipping Green drive and power savings ranged from 15% to 25% across the test.

With regard to transfer performance, I expected to see the standard desktop drives easily outpace the low-power drives, but in fact the results were mixed across the devices. On a few of the servers – the QNAP TS-259 Pro+, the ASUSTOR AS-609RS and QNAP TS-451 I saw a small (2-8%) write speed gain from the slowest Green drive to the the fastest standard drive. On other devices, such as the Windows 8.1 “home server”, the WD Blue 1 TB desktop drive was actually slower than the WD Greens. A stronger trend was found when it came to read performance, with a 7-9% gain seen on the QNAP TS-259 Pro+, ASUSTOR AS-304T and AS-609RS.

So, in the desktop drive arena, the Green drives proved to do their job overall in reducing power consumption with only a minimal performance hit.

NAS Drives

We step up from Desktop drives to a relatively new class of storage – NAS Hard Drives. Emerging in mid-2012, NAS drives ship with specialist firmware that tailors the operation to be more suitable for network attached storage devices. There are two big players in this sector – Seagate’s NAS hard drives and Western Digital’s Red series.

wd-red-6tb

Seagate’s specialist firmware is called NASworks, and claims improved drive reliability courtesy of three core features. Error-recovery controls maintain the integrity of data stored in a RAID array. Typically, if a hard drive takes longer than seven seconds to acquire data (which could happen if the drive is attempting to recover data from a damaged sector), a NAS device will assume that the hard drive has fallen out of the array and will initiate a full rebuild of the array, which can take hours, if not days to complete. Unlike a standard desktop drive, Seagate’s NASworks firmware ensures the NAS hard drive stops tying to recover the data before those seven seconds have elapsed and will notify the RAID controller that it needs help recovering the data. Rather than initiate a full rebuild, the RAID controller should instead trying to recover the data from its redundant backup, saving the user the pain of impaired performance during a RAID rebuild.

The second feature included in Seagate’s NAS hard drives focuses on vibration. As you’d expect in a mechanical device, the high-speed platter rotation in desktop hard drives creates vibration – minute vibrations, but vibrations all the same. Those vibrations may not be a problem in a single drive desktop PC, for example, but in a multi-bay NAS device, the effect can be amplified and, according to the hard drive manufacturers, can impair performance as a result. So, Seagate include a feature called Dual-Plane Balance which balances the hard drive motor, minimising vibration. In Seagate drives, this feature works best for NAS devices with up to five bays – the company recommends Enterprise drives, with additional features to manage vibration, in larger devices.

Finally, let’s talk Power Management. Standard Desktop drives are built with a power management profile to suit the working week – they’re not expected to be running 24/7. In Seagate’s NAS hard drives, the power management profile is tailored for 24/7 operation, with the necessary settings to go into the relevant sleep or standby mode when required. Seagate says that this reduces power consumption and improves drive reliability.

Over on the Western Digital side of the fence, WD Red hard drives tell a very similar story, albeit with slightly different words. Their NASware 3.0 firmware now supports devices up to eight bays (compared to Seagate’s five) with similar features. For NAS devices between eight and sixteen bays, a WD Red Pro range of drives is available and is also recommended for rackmount devices.  3D Active Balance Plus is the name given to WD’s dual-plane balance feature, for vibration control, available across WD’s 3.5″ Red hard drive range (2.5″ Red drives are also available but do not support this feature).

Like the Seagate NAS drives, similar error-recovery controls and 24/7 power management profiles are included in WD Red drives to improve operation and reliability. An additional data protection feature, Command Completion minimises the data corruption in the event of an unexpected power loss by completing the command in process before shutting down.

seagate-nas

Western Digital claims greatly enhanced reliability for the NAS drives over standard desktop drives equating to a 35% MTBF improvement. MTBF? Mean Time Before Failure – no hard drive manufacturer can claim a drive will never breakdown, so from their testing, they have traditionally calculated an MTBF figure, outlining the amount of operating hours a drive will last, on average, before a failure. That said, while quoting MTBF improvements for WD Red drives, Western Digital says elsewhere on their website that they don’t calculate MTBF figures anymore, but rather quote drive reliability in Component Design Life (CDL) and Annualized Failure Rate (AFR). The Component Design Life of a WD drive is quoted at 5 years and the Annualized Failure Rate is less than 0.8%. Seagate too have moved away from MTBF and now quote AFR figures (at <1%) for their drives.

So, what NAS drives have we selected for our test? On the Seagate side, we have the Seagate NAS 4 TB hard drive (ST4000VN000). At the time of writing, it’s the highest capacity NAS drive available from Seagate. From Western Digital, we have two generations of NAS hard drive. The 2 TB WD Red (WD20EFRX) running NASworks 2.0 as well as the latest generation of WD drives, the 6 TB WD Red (WD60EFRX) with NASworks 3.0. Both WD drives have a quoted MTBF of 1,000,000 hours (yes, I know they said they don’t calculate MTBF anymore, but it’s stated on their marketing materials!)

NAS Hard Drive Benchmarks: NAS Hard Drive Results

While there are only a few NAS drives on the market at the moment, this was a great chance to see how Seagate and Western Digital’s NAS drives stacked up against one another. Reasonably similar features, reasonable similar hardware should equate to reasonably similar results. Right? Actually, I found some notable differences. The first comparison was on power consumption – an almost universal trend saw higher power consumption from the Seagate 4 TB NAS drives than either of the Western Digital drives, which was a surprise. OK, we were testing drives of varying capacities – 4 TB Seagate drives vs 2 TB and 4 TB WD drives, but power consumption was not proportional to capacity.

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25 comments

    1. That’s a great link! Just remember that those guys are in a datacenter and you may not be hammering your drives as hard at home or in your small business! But all things being equal, the reliability comparison between the drives they’re using is interesting.

  1. Hi,

    WD Re drives spin at 7200rpm, not 5,400

    if you actually click the link in your own paragraph you will be taken to an amazon page where the title proclaims the Re to be 7,200rpm

    “Well, if you check back in our specification table, you’ll see that the WD Re drives spin mire slowly than the Se drives – 5400 RPM vs 7200 RPM and that translates into lower power consumption. ”

    I suspect the confusion is because you have looked up the specs sheet for the old RE4-GP drives, which are NOT part of the same series as their current model Re/Se/Xe enterprise drives (one is RE , one is Re .. isnt that clear), but were in fact raid-optimised GP (green power) drives

    here’s the Re specs page on the WD site, clearly showing every single Re drive spins at 7,200 rpm

    http://www.wdc.com/en/products/products.aspx?id=580#Tab3

  2. Those Seagate Barracuda Desktop drives are no longer on the QNAP compatibility lists, as far as I can tell.

  3. Thanks Mr. Walsh for a great article.
    In my opinion the more expensive drives would be worth it if their guarantee was longer.
    Say 3 years for a desktop drive, 6 years for a NAS-drive and 10 years for a Enterprise drive.

  4. Hi Terry: I did my own review of drive reviews and wound up picking four Western Digital Red 4 TB drives for my home server. Unfortunately I intended to use WHS 2011 and 4TB drives are not supported for server backup so instead I’ve installed Windows Server 2012 r2. I was able to use the RAID5 array built with WHS 2011, interestingly. There are drive reliability results from an increasing list of other writers/publishers that agree on the following: Western Digital is making the most reliable drives now. WD also now owns HGST which was formerly IBM and those drives, according to reviewers, appear to be enterprise-class drives packaged and sold as consumer drives. They are the most reliable but also count now as WD drives. Eric

  5. “equating to a 35% MTBF improvement. MBTF? Mean Time Before Failure”

    Direct quote from your review.

    Dude. Once, even twice I can ignore it. SEVEN TIMES. Seven times you made the typo, even in the expansion of the actual acronym. Every time I stumbled across it, I kept thinking, “WTF is MBTF? mean between time failures? nawww that doesn’t make sense. Maybe the manufacturers came up with a new buzz word…nnnnaaawwww….”

    Sorry, for this, but it’s so I feel better. MTBF MTBF MTBF MTBF MTBF MTBF MTBF.

  6. I’ll be buying a QNAP TVS-871 when they come out next month. This article was well written and confirmed what I was already leaning towards. I’ll be replacing a 10 year old HAMMER drive (with two 1 TB drives mirrored). The funny thing is the HAMMER drive is still running like a champ but with videos and family photos growing I’d rather setup RAID 6 to protect these things.

  7. Very interesting options… I am looking into this just stay have independence with all of my own data. I wonder if this might become the next major wave for home computing? Everybody keeping their own data on their own servers. Sharing it with “Torrent style” software so as to have more control, instead of being at the mercy of social media and other aggregators. Heck of a market growth potential for the server hardware guys if the software is there.

  8. thinking about the pratically identical speed of all the NAS and drives you tested…
    didn’t read all the article, but I think you didn’t mentioned the speed of the net where you tested the devices…
    Gigabit ethernet “should” provide a maximum theoretical speed of 125MB/s…real speed is less than that…
    so, what I think is that all the devices combination you tested, probably had different results…for example, some of the NAS used have double Gbit port, maybe trying to do speed test with different PC over the same network with 2Gbit port connected the results are different and permit to understand which couple (drive/nas) is faster than another. The only useful information I can see is that speed slower than 90MB/s determine which drive or nas are worst than the others…

      1. I wasn’t obviously talking about internet…local network has its maximum speed too! (or you think wires at home are faster than the star trek ship?) and, it’s funny, it’s almost the same maximum speed you measured on all the devices tested!!! I want to do an example like yours of the focus vs. the ferrari…saying that all the devices go to 100MB/s is like saying that 130km/h is the maximum speed of both a focus and a ferrari just because they’re respecting the speed limit on the highway.
        A confirm of this is the little note that QNAP add to some of their speed test, that says that they tested a NAS using 2PC simultaneously to reach speed of about 200/250 MB/s

        1. The only way to get an absolute speed test out of a set of drives is to
          pull the data on a 10GB network so that the network is not s speed
          limiting factor and to ensure that the system transferring data for the
          test is faster than the spinning disks being tested by using an array of
          SSDs. The trouble is, at some point, you will probably still be
          limited by a hardware speed limit.
          I have a set of 10 Western Digital Re drives that will push enough data to flood even a 10GB card with all it can take.

  9. Outstanding article. I had gotten lucky and selected a lot of 4Tb WD Red NAS HDD units for 3 Synology NAS units, and am very pleased with the performance and reliability. On a 4th Synology unit I ended up with some Seagate NAS class HDD units, and in fairness I have had no problems with them. The WD Red HDDs do run a little cooler than the Seagate HDDs, per the Synology reporting interface.

  10. I am building a home NAS system. I will run Unraid as my OS. I would like to use a WD Black desktop 1tb drive as my cache drive. Would that be a good choice or should I use an actual WD NAS RED instead? I plan to use 4 1tb WD Red drives for the actual storage, 1 2tb WD RED for Parity and as I said 1 WD Black desktop drive as my cache. What are you thoughts on this idea?

    1. Without knowing why you need cache, my inclination would be to use more real memory or SSD for cache and save the 3 1/2″ bay for additional storage or later expansion space, if you can find a place for 2 1/2″ SSD that doesn’t fill a disk bay.

      1. Thank you. I will be using an SSD as a cache drive within the NAS system. That leads to an additional question: Since I am using 4ea 1TB drives for storage, 1ea 2TB for parity is there a size limit to using an SSD as a cache drive? I was thinking of using a 240gb SSD but if a larger or an additional 240 drive would be better than that is what I will do.

  11. Hi,

    Interesting read. It would be great if future update of this article also include noise measurements and more recent drives.
    In my case, I noticed that some older samsung HD103UJ are much noiser than my WD 30EZRX. I wish I had done better research back then.

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