Stress Testing and Effects of Prolonged Usage

Readers of our other NAS reviews might be aware that we are in the process of building a NAS testbed capable of testing mult-client scenarios. While the details of the testbed will come in a separate piece next week, we will describe the relevant part of the system in this section. Since the Synology DS211+ performed the best amongst the three tested NAS systems and is also officially recommended by WD, we chose it for stress testing. The DS211+ was configured with 2 x 3TB WD Red drives in RAID-1 and connected to a Zyxel GS2200 switch. A dual Xeon workstation was set up to run 12 Windows 7 VMs (each with a dedicated physical disk and a dedicated GbE port connected to the switch). Scripts were set up to do a synchronized data copy from each VM to a Samba share on the DS211+. We paused the scripts after the NAS became 30%, 60% and 90% full to repeat our benchmarks from the previous section. Each 30% step took approximately 15 - 20 hours. A screenshot of the status of the Samba share after the process was completed (90% full) is shown below.

At 90% full, the NAS had more than 7 million files in almost a million folders. 95% of the files were between 0 and 512 KB in size. 1.8% were between 0.5 and 1 MB, 2.8% between 1 and 10 MB, 0.2% between 10 and 100 MB, 0.03% between 100 and 1024 MB, and 360 files were more than 1 GB in size.

The results of running the NASPT / robocopy benchmarks at each stage are provided in the graph below. Note that the NASPT tests were run from one of the VMs in the new testbed, and some of the results could be slightly different from what was obtained with our Summer 2012 NAS testbed.

The above benchmarks show that the performance does degrade (particularly for write intensive benchmarks) as the NAS fills up. However, the big gap that we saw in the raw drive performance (in the HD Tune Pro benchmarks) doesn't seem to be as evident when the disk is being used inside a NAS. In any case, it is always advisable to run any NAS below 90% of the capacity.

Performance Metrics and Power Consumption Final Words
POST A COMMENT

85 Comments

View All Comments

  • vgray35@hotmail.com - Saturday, August 18, 2012 - link

    Good reliability and low power consumption is my first criteria, but the latter cannot be used to sacrifice the former. Both criteria lead to longer life cycles. The lower power GREEN and BLUE drives are designed with an eye towards rather low cycle life, and therefore low power as a criteria for these drives makes no sense whatsoever. It seems the only way to get reliability is to stay away from cheap low end consumer hard drives which is most of the drives out there.

    To me I do not differentiate between standalone, external storage, second hard drive, desktop or laptop, as these all demand good reliability and low power consumption for the best possible price. Performance is the next important criteria, but it is a fallacy to expect good performance from a 5400 rpm low power drive, and I no reason why the minimum spindle speed should not be 7200 rpm. Lower spindle speeds appear largely in the realm of low end consumer drives where reliability is very poor. Hard drive crashes plague the computer world because the majority of products are bad in the extreme, long lasting cheap consumer drives in some configurations notwithstanding. Just because someone says that they obtained a 3 year life span with cheap consumer drives, does not make them good drives generally, because that long life example is not typical for the majority of real world usage conditions. I now have a lower boundary criteria - "if it does not last in a laptop then it is not good for any purpose bar none".

    So all this translates to never buy anything less than 7200 rpm to ensure a good shot at performance, and search for good drive designs with the lowest power consumption to have a good shot at longer life spans in any situation. Picking a low power drive simply to achieve low power drain, is more often than not the same thing as purposely selecting a LOW quality drive in terms of performance and cycle life, and such a definite requirement is very rare indeed. Why bother - extremes of low power means low performance, and often also very short cycle life.

    There is very rarely a situation which does not demand extremes of temp cycling of the hard drives, which is what will lead to shorter life spans and hence poor reliability. I have come to the conclusion the classifications of standalone, external storage, 2nd drive, laptop, etc are not particularly useful if reliability and performance are important - and since when are these never important. These classifications have become justifications by the manufacturers for designing - "only as good as needed" devices. It is an excuse for designing crap product

    Western Digital BLACK or RED is a minimal consumer drive quality level to be used in any application, and anything less reliable should never be graced with your dollars. Less reliable drives lasting for years in some particular situations is largely a myth - it happens only if certain criteria are meet, namely, low loads and small temp cycling, which rarely occurs in the real world of consumer computing. When looking at Western Digital drives, always stay away from GREEN and BLUE drives, simply because components are designed to last only under certain special conditions, and I believe these special operating conditions in practical terms are just a myth. In essence these manufacturers (marketing honchos) give credence to conditions of "LOW THERMAL CYCLING", which they then decree is a significant portion of the market place, when in reality it really does not exist, and only gives them an excuse to design "only as good as needed" devices. The existence of the low quality drives permits them to charge more than they normally could for the better drives. Don't believe the hype, the more expensive drives are required for good reliability and performance. apparently good news about GREEN and BLUE drives notwithstanding.

    Don't ever buy too cheap, if you want to avoid repeated disk crashes, and there is nothing wrong with periodically replacing working drives with new ones periodically to avoid the inevitable disk crashes. Even good drives eventually fail. If the manufacturer specifies a 3y warranty, then replace the drives every 2 years.

    You asked for advise on selecting drives, but what I am giving you really reads as a recipe for spending more money. You will not regret it.

    What does "Drives certified for 24/7 really mean?" It means better able to handle temperature cycling arising from inadequate cooling or heavier loads, while still permitting reasonable cycle life. Reliability comes from 24/7 certification, with drives designed to handle extremes in both peak temperature and temp cycle, and drives not so certified belong to the mythical world of operating conditions where thermal cycling is less important. I have to realize all situations require 24/7 certification and to believe otherwise is a risky business.

    So buy BLACK drives for all your applications as a minimum and occasionally you will need RED for better reliability. Personally I reckon RED only for me after prices have settled in the months ahead. I wonder if they make 2.5" RED drives.
    Reply
  • Peroxyde - Saturday, August 18, 2012 - link

    Thank you very much for the thorough explanation. With too much emphasis on NAS usage with the Red, I am still wondering if technically they can still function as a single drive outside of a NAS. Should people who don't have NAS device avoid buying the RED drives?

    Let's try a real example:

    USB 3.0 External Drive: I hesitate between Caviar Black 1 TB, 5 years warranty, $100 et WD Red 2 TB, 3 years warranty $140. I am torn between the 5 years warranty of the black and the 2TB of the red. Reliability is the most important. This external drive will travel often and will be frequently powered on/off. What would you choose?
    Reply
  • vgray35@hotmail.com - Saturday, August 18, 2012 - link

    BLACK is cheaper but quality is a lot better than GREEN and BLUE, and BLACK may well be a good choice reliability wise.

    If RED is good for multi-drive RAID.operation, then it is definitely very good in terms of reliability in single drive applications. The 5 year warranty on BLACK seems a better deal right now. RED is new and needs time to unravel its true nature. BLACK has 300,000 load/unload cycles while RED is rated at 1,000,000, but the BLACK drive draws a lot less power. I would go with BLACK's 5y warranty instead of RED's 3y warranty

    Make sure you have enough cooling and you know the drive's temperature during heavy loads.

    Reply
  • Peroxyde - Saturday, August 18, 2012 - link

    Cool thx. BTW, In the example above Black is not cheaper. It costs $100/TB while the Red is $140 for 2TB. I'll follow your advice, will buy the 1TB Black for now. Reply
  • vgray35@hotmail.com - Tuesday, August 21, 2012 - link

    I have just read the SPCR review of RED drives, and these may well be a better choice all round over the BLACK drives, especially given the energy efficiency numbers, and the fact that 7200 rpm drives are not able to consistently outperform these 5400 rpm RED drives.

    Note that the 1T RED drive performance is quite a lot less than the 3TB drive, but is more energy efficient. The 3TB performance is good.

    That RED 3y warranty is likely based on a NAS configuration (a harsher environment), which means a standalone drive is likely approaching a 5y warranty equivalent. I am beginning to change my mind on that BLACK drive purchase even with that 5y warranty.

    http://www.silentpcreview.com/WD_Red
    Reply
  • Watwatwat - Saturday, August 18, 2012 - link

    Of course they function like any other drive outside of nas.

    worrying too much about reliability misses the point, you should buy two because one will fail with your data, its just a given, you need backup. don't buy yourself a false sense of security.
    Reply
  • vgray35@hotmail.com - Monday, August 20, 2012 - link

    I agree. Use that 2nd hard drive to replace the 1st drive BEFORE the warranty runs out, regardless of whether the 1st drive still seems OK.

    When you buy higher reliability drives this is not false security, just good business. False security is when one fails to also use backups.

    Using backups, and hope that cheap GREEN and BLUE drives will be mitigated is a false hope. Recover from a failure is invariably always a very expensive proposition.

    Isn't buying two the point about satisfying that worry? Backups are always a pain, cost money and time, and are painful when you have to resort to using them. Changing drives early invariably affords less pain.
    Reply
  • SunLord - Saturday, August 18, 2012 - link

    WD Red is un-gimped Raid friendly version of Green drive just like the RE drives are un-gimped raid friendly versions of Black drives. The only real differences between Red and Green is the firmwares they ship with having different settings the internals are all identical just like it is with Black and RE drives. I will admit the I've not taken apart a red drive but I have taken apart a Black and RE 1TB drives made with in 3 weeks of each other and they were 100% identical save for the stickers any Reply
  • vgray35@hotmail.com - Monday, August 20, 2012 - link

    And yet experience under load yields a different result, despite the fact that they look the same inside. There is something else afoot here besides firmware. Reply
  • Dzban - Saturday, August 18, 2012 - link

    1. Any good recent 7200 RPM drive
    2.same
    3.same but you could use "green" type drive if you would store
    not frequentlyu used files like media
    Reply

Log in

Don't have an account? Sign up now