Toshiba's $7000+ 400 GB SSD: SAS 6Gb/s, SLC Flash, And Big Endurance

MK4001GRZB : Great Endurance, Fast Reads, Slower Writes

The cadre of IT managers who make purchasing decisions for big enterprises don't just read reviews and buy pallets of storage devices. Rather, they spend weeks and months with new technologies in isolated servers, testing their mettle before deploying into production. In many performance-sensitive workloads, SSDs make a lot of sense. They can even save money when they replace a much larger quantity of disk drives. But reliability is of the utmost importance and, by extension, endurance receives attention as well.

As a result, it's difficult to render final judgement on an enterprise-class SSDs. Performance isn't the headliner that it is in desktop environments. Rather, it shares the spotlight with data security, and that's a very difficult variable to quantify.

We can determine performance over the course of a weekend (even taking steady states into account). If the only thing you care about is raw throughput, you could conclude that Toshiba's MK4001GRZB delivers excellent read speed, but is generally matched by desktop-class drives like Intel's SSD 520 that cost a lot less and facilitate better efficiency. The MK4001GRZB sells for more than $7000, while a 480 GB SSD 520 is available under $1000. A 200 GB P300 goes for somewhere around $2000, which can't stand up to the Intel drive, but it also employs SLC NAND, too.

Reliability is the real challenge. Statistically, a handful of reviews is insufficient for crowning one company or another the best for keeping data secure. To really gauge reliability, you'd need to watch the failure rate of a large population of SSDs subjected to the same workload. Why? Because solid-state storage changes its behavior based on activity, which cannot be said for hard drives. Right now, vendors only seem willing to cite the return rates from distributors, which generally involve fairly small sample sizes. Invariably, it'll take more time and a study like Google's own independent analysis of failure trends to shed more light on how SSDs compare.

Endurance is related to reliability, but certainly not the only (or most important, even) determinant of it. It's possible to test and estimate the rated longevity of an SSD using SMART (Self-Monitoring, Analysis and Reporting Technology) tables and a bit of math. Unfortunately, it is a very time-consuming process. In order to give you an idea of what it took for us to present endurance figures for Toshiba's drive, we had to write to the MK4001GRZB for 41 days, 24 hours a day, to get the MWI to drop 1%. In the process, we wrote approximately 900 TB worth of data. And that figure only applies to a purely sequential workload. Estimating endurance for random access would require a separate test, as write amplification is higher. We're not sure how much longer testing would have taken, but it could have been as long as three or four months.

As a result, our conclusions are and will always be admittedly less complete than a review conducted over the course of months or even years. But that's the trade-off for also publishing something in a timely manner. This could have been a great candidate for a long-term story where we put the rubber to the road and go ahead with calculating random I/O endurance as well. Alas, with a $7000+ price tag, it's understandable that Toshiba wanted to get the drive back sooner than later.

At the end of the day, based on our testing, we can say that Toshiba's MK4001GRZB offers very fast reads, slower write performance, and amazing endurance in sequential workloads. The last point can't be understated. In an environment pushing sequential writes all day, every day, it'd take more than 11 years to use up the 400 GB model's rated P/E cycles. That's well beyond Toshiba's five-year warranty. And so, when it comes to enterprise storage, the MK4001GRZB  shows us why SLC flash is still top-of-the-line. 

  • compton
    Good job, Mr. Ku.

    Perhaps the Enterprise SSD Fairy will bring you a Hitatchi UltraStar with Intel's 6gbps controller. I'd be eager to see how it compares.

    There is no substitute for SLC though.
  • nebun
    $7000 any company willing to pay this much for an SSD is fullish
  • bennaye
    nebun$7000 any company willing to pay this much for an SSD is fullish
    ...fullish of cash? Definitely. Foolish? Probably not.
  • nebun
    bennaye...fullish of cash? Definitely. Foolish? Probably not.damn the english language.....there are way to many words that sound alike
  • confish21
    How is this $7000 drive profitable over it's competition again?
  • nitrium
    Why is the 4KB Random read/write performance shown as IOPS, but 128KB and 2MB performance is in MB/sec? What speed (in MB/sec) does this drive achieve in 4KB? I guess I could calculate it from (IOPS * 4KB) / 1024 (I think that's right), but why should I have to?
  • spazoid
    amdfreakIt is too expensive for the performance it offers. You can get a RAID array of many Intel SSDs beating Toshiba in every segment.
    You've clearly not understood the purpose of this article. Stick to commenting the desktop drive reviews in the future, please.

    Thank you for this review, and especially your estimations on the endurance of the drive. It's something that's damn near impossible for us IT professionals to get accurate estimations of in the real world. For some reason, bosses tend to want the expensive hardware to be put to use instead of being thoroughly tested.

    More of these types of articles please! :]
  • @spazoid, so you are telling me that you are willing to pay 10x for an endurance of 3x over the INTEL 520 SSD?
    Even when the INTEL SSD already has an endurance longer than your refresh cycle for your tech stack?
  • EJ257
    frozonicLOL, i can just imagine myself in ten years telling my kids that we had to pay 7000$ for a 400gb that time we are gonna have 400+ TB ssds
    "Back in my days storage drives used to have moving parts. Now its all solid state."
  • jaquith
    I own a small data center and thankfully have access to a 'major' financial institutions test data, and I agree with your conclusions especially regarding deployment into production. $7K SSD is a tough call with a 5-year, but if it were 7~10-year then probably an easy call.

    Unlike super-sized enterprise which I am not, the cost/benefit calculations would be difficult for myself. I know firsthand the money that i.e. financial institutions push into their data centers, and for those folks $7K isn't out of the question.

    Interesting SSD and if the prices come down and warranty extended then IMO it would be something to consider and compare against Intel's products.