Intel Optane SSD is the Magic Key to Unlocking the Latest Cryptocurrency: Chia
Allison Goodman, Sr. Principal Engineer, Optane Solutions
Storage rarely makes the headlines, even the technology headlines. No one spends time thinking about their storage drive, especially not the differences between hard drives and solid-state drives, SATA and NVMe protocols, or client and enterprise drives. The technology news as of late has surprisingly been filled with news of drive shortages, the high rates of drive wear out, and big mark-ups on seemingly boring, standard drives. Which leads to the question of why? Why the sudden excitement about storage drives and how does Intel Optane SSD fit in?
The answer is Chia. It’s not the magical seeds packed with vitamins for endurance runners or the plant pet that grows sprouts for hair. Chia Network is the latest exciting entry in the blockchain-based cryptocurrency market. Chia is different from the more popular and well-known Bitcoin, and many other cryptocurrencies, as it is based on proof of space and not proof of work. And that idea of space means taking advantage of storage.
The key to farming and making money with Chia is to plot quickly and efficiently, and then move those plots to a much cheaper, slower storage to farm. SSDs are commonly used as temporary storage to speed up the process and handle the large number of writes that occur during the generation of Chia plots. A plot file is then moved from SSDs to hard drives for longer-term storage where periodically users farm their plots to see if it has a winning “proof”, broadcast from the Chia Network. Chia advocates using enterprise NVMe flash drives as the drive of choice for plot temp drives as they can sustain high throughput and have higher endurance. Consumer NVMe SSDs are not generally optimized for high endurance because the average user doesn’t actually write much data over the lifetime and thus these drives are more subject to wear-out during the plotting process. A balance of performance and endurance on the drive is key to efficient and effective plotting.
The best-in-class throughput and endurance NVMe drive is an Intel® Optane™ SSD. The first generation, Intel Optane SSD P4800X set a new standard in high endurance, high performance data center drives. Intel’s recent announcement that their second-generation Intel Optane SSD P5800X is available to consumers received rave reviews. Intel Optane SSD P5800X brings 67% higher endurance (100DWPD vs 60DWPD) than the first generation and even more performance as it supports PCIe gen4 bandwidths. In fact, Jonmichael Hands, VP of Storage Business Development at Chia, claims to have achieved the fastest plotting time for k=32 plot with Intel Optane P5800X SSD.
The active Chia community is quickly evolving and so are the plotting tools. According to Chia, the latest plotter, madMAx43v3r, is a significant enhancement in plotting times, as well as a simplification to the initial plotter that required balancing more performance and space aspects of your overall plotting system for optimal plotting times. With its streamline plotting, single k=32 plots with madMAx have come down from hours to minutes. And yes, the k=32 plot times with Intel Optane SSD on this new plotter are still setting records. (link)
This latest plotter development focuses more attention on the temp drive choice, as a mid-range system can provide enough compute for fast plot times, and the amount (GiBs) of temp space required to plot is reduced enough that just one or two temp drives is reasonable for serious plotting. The Chia community crowdsources a “Chia plotting performance” leaderboard that showcases system configs for optimizing plotting investments and configuring for parallel plotting. Many of the top plotting times use Intel Optane SSDs for temp drives. (In these impressive configs, Intel Optane SSDs are performing slightly better than even DDR4 RAM drives.) For the remainder of this blog, the focus will be on temp drives for plotting, and why Intel Optane SSDs are perhaps the perfect temp drive.
“Chia is an exciting technology that allows the blockchain to be secured by storage, using a breakthrough consensus called proof of space and time. Generating the plots does require a one-time use per plot file of compute and temporary storage space. The storage requirements for plotting are high sustained write bandwidth, mixed workload performance, and very high endurance. Sound familiar? Optane SSDs are the best in the world at every single one of these metrics and provide insane performance, value, and longevity for serious Chia farmers.” — Jonmichael Hands, VP Storage Business Development at Chia Network
Why Intel Optane SSDs are the perfect temp drive for Chia plots
Scour the web for info to get your chia plotting systems up and running and you will find lots of pointers towards using SSDs and specifically high-bandwidth SSDs for your temp drive. A quick view of the bandwidth and writing required to sustain a Chia plot workload will highlight why. That leaderboard shows plotters easily achieving 7–9GiB/min of throughput while plotting. while plotting.
Intel Optane SSDs are optimized for heavy write workloads and most importantly able to handle both reads and writes at the same time with incredible efficiency and low latencies. This is key because when plotting, the temp drive is both writing and reading. If you just look at writes, you’ll likely max the drive out at half the total supported bandwidth. The more plots in parallel and the more random the workload on the drives gets. A PCIe Gen 3 Intel Optane SSD P4800X drive can sustain 2.3 GB/s total throughput (reads/writes), and even more importantly for parallel plotting 2.1GB/s with random 4K writes. The PCIe Gen 4 Intel Optane SSD P5800X drive goes even further with 7.4GB/s sustained throughput and 6.5GB/s with random 4K writes. At these blazingly fast speeds, just one Intel Optane SSD can keep up with the full bandwidth of the PCIe bus. This means your drive speed is not the bottleneck to your Chia plotting investment!
Speed is only half of the consideration in choosing a temp drive, the other is endurance — or how long your drive will last before it wears out and can no longer retain data.
Additional scouring of Chia community resources and comparisons of temp storage drive options will quickly reveal a bunch of storage terms like DPWD (drive writes per day), TBW (terabytes written), and WAF (write amplification factor). What do these really mean and why do you need to know? Because serious Chia plotting will quickly wear out drives, limiting the life span, especially with the latest madMAx plotter speed of plotting.
Before I show you how well the endurance of Intel Optane SSD supports plotting, let’s walk through the formula of how these terms come together to inform a decision on what type of temp drive endurance you need, as a function of time to k=32 plot.
First, let’s define what space is needed to plot:
- TBWperPlot: This is the terabytes, TB, required to be written to generate one k=32 plot. This is set by the plotter software. With the madMAx plotter, it means that in order to make one 101.3GB plot, the system has to write 1.317TB of data, 13x the amount of data for the final plot. (This also says the plot software write amplification is 13).
Using a higher capacity drive will lead to higher TBWperPlot. - DriveLifetimeWrites: This is the total petabytes, PB, of writes a drive can do before it wears out and can no longer accurately store data. Drive vendors have different ways of showing this, drive writes per day or total petabytes written.
For TBWperPlot = 1.317TB, it would be easy to take a drive that advertises a lifetime of 1.32 PBW and say that drive could be used to write 1,022 k=32 plots. Sadly, it is not nearly this straightforward.
For the endurance of the temp drive, the calculation also needs to consider write amplification of both the Chia plotting as well as the assumed write amplification when advertising the lifetime petabytes written.
NAND drives have an inherent write amplification factor (WAF) within the drive to account for the fact that NAND flash must be erased before written and the size of erase blocks is much larger than the size of written pages. This creates the need for garbage collection within the drive and means for every write you send from the system, the NAND drive typically does between 1x-5x the number of writes. The heavier the write workload and more random the write workload, the higher that write amplification is. Chia is not a particularly high WAF workload, but it can easily increase with more space you fill on a drive and with more parallel plots.
Unfortunately, for WAF, many times you will need to guess, unless you take the time to pull SMART logs of your drive for total device writes and host writes and calculate it. (Chia also has a handy endurance wiki)
Intel Optane SSD is a write-in-place media where the erase blocks and write blocks are the same size. This means the write amp is effectively 1 for all workloads and makes Intel Optane SSDs the “easy button” for not needing to worry about this part of the formula and not needing to sift through the different product specs and SMART logs to figure out write amps for your temp drive of choice.
So, now we introduce 2 more factors to understanding endurance for plotting:
- PlotOnDriveWAF: Write amplification for Chia plotting software on the drive of choice (Intel Optane SSD = 1, for NAND-based drives, it will vary greatly depending on spare capacity and how random the workload is, typically 1.2–5)
We’ll be generous and use the low end of the write amp. - DriveEnduranceWAF: Write amplification that drive vendor used when measuring to advertise the lifetime drive writes. Intel Optane SSD = 1. For NAND-based drives, this varies. Typically, it will be around 2–2.5 for drives that quote an enterprise JEDEC standard.
Now, accounting for write amplification, the equation for how many k=32 madMAx plots for a given drive, looks like this:
TotalLifetimePlots = (DriveLifetimeWrites x DriveEnduranceWAF) / (TBWperPlot x PlotOnDriveWAF)
TotalLifeTimePlots* is now a key metric for judging how efficient your investment is for a Chia temp drive.
Just take a look at how well enterprise Intel Optane SSD compares as the “easy” button for not worrying about drive wear out.
The chart shows a representation of a typical NAND client drive endurance and NAND high endurance enterprise drive alongside Intel Optane SSDs available to the Chia community. As you can see, the enterprise Intel Optane SSDs are the top choice when it comes to supporting lifetime plots. Maybe doing that many Chia plots is not in your future, no worries. The great thing about this superior endurance is you can plot for a while, and still have plenty of life left on your Intel Optane SSD to do other things! It is an excellent investment for even the less committed Chia plotters.
Tying back in the speed component, to make use of this much endurance economically, you must have a high-performance drive. The balance of speed and endurance is critical. The leaderboard shows just how fast you can plot on given systems, and you can see how fast you can wear out a drive. A Samsung 983 DCT SSD could be worn out in 1 month! Whereas an Intel Optane SSD is good for well over a year or more if it is plotting 24 hours a day, 7 days a week!
Speaking of investments, the Intel Optane SSD value would not be complete without taking into account pricing. Does this value come through when drive prices, ASPs, are taken into account?
Yes! In a quick comparison of endurance on drive options, enterprise Intel Optane SSD easily shines as a great, cost-effective option for a plotting temp drive. Check out this link to the Chia wiki for drive endurance and pricing comparison. Without replicating all the data here, the Intel Optane SSDs provide consistent, low costs per k=32 plot.
Conclusion
Intel Optane SSDs allow you to maximize your Chia temp drive investment for performance and endurance. They provide a unique opportunity to pay off the drive costs with Chia plotting and still have plenty of endurance left to use for more plotting or additional workstation or server usages.
Chia, the new cryptocurrency entrant, the “green cryptocurrency”, based on proof of space is perhaps one of the best workloads today to showcase the revolutionary value of Intel Optane SSD when it comes to needing both high write performance and high endurance.
*Graph based on TotalLifetimePlots formula calculations
Notices & Disclaimers
Performance varies by use, configuration, and other factors. Learn more at www.Intel.com/PerformanceIndex.
Performance results are based on testing as of dates shown in configurations and may not reflect all publicly available updates. See backup for configuration details. No product or component can be absolutely secure.
Your costs and results may vary.
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