Plotting the Crypto Coin Storage Farm

The recent craze of the Chia cryptocurrency got me excited. Mostly because it uses storage as the determinant for the Proof-of-Work consensus algorithm in a blockchain network. Yes, I am always about storage. 😉

I am not a Bitcoin miner nor am I a Chia coin farmer, and my knowledge and experience in both are very shallow. But I recently became interested in the 2 main activities of Chia – plotting and farming, because they both involved storage. I am writing this blog to find out more and document about my learning experience.

[ NB: This blog does not help you make money. It is just informational from a storage technology perspective. ]

Chia Cryptocurrency

Proof of Space and Time

Bitcoin is based on Proof-of-Work (PoW). In a nutshell, there is a complex mathematical puzzle to be solved. Bitcoin miners compete to solve this puzzle and the process uses high computational processing to solve it. Once solved, the miners are rewarded for their work.

Newer entrants like Filecoin and Chia coin (XCH) use an alternate method which is Proof-of-Space (PoS) to validate and verify the transactions. Instead of miners, Chia coin farmers have to prove to have a legitimate amount of disk and/or memory space to solve a mathematical puzzle, conceptually similar to the one in Bitcoin mining. In the beginning, this was great for folks who have unused disk space that can be “rented” out to store the crypto stuff (Note: I am not familiar with the terminology yet, and I did not want to use the word “crypto tokens” incorrectly). Storj was one of the early vendors that I remember in this space touting this method but I have not followed them for a while. Their business model might have changed.

Of course, seeing that Chia coin (XCH) is now worth over USD$1,000.00 in less than 2 months, there is a frenzy of creating plots (digital demarcated storage areas) and disk farms (large capacity digital storage) to grab this new wild, wild west resource. In the pandemonium, we have seen

• [ May 3, 2021 ] Vietnam faces hard drive shortage due to Chia mining craze in China
• [ May 6, 2021 ] A new cryptocurrency called chia could push up hard drive prices for everyone
• [ April 19, 2021 ] Storage shortage imminent with new Chia cryptocurrency

Chia has now gone even further with introducing the element of Time to Space, combining them to make Proof-of-Space-Time (PoST). Incorporating a time variable called VDF (Verifiable Delay Function) through servers called Timelords, the transactions can be quickly verified to complete the block, and forwarding the sequence of the blockchain.

This combo of the amount of storage capacity (Space) promised to the mathematical puzzle and how long the storage is available (Time) are key for the Chia (and other related cryptocurrency) farmers to earn their rewards. The selected hash function will choose the plots compatible to the challenge to participate in the block chain transactions. According to Chia Network, this PoST blockchain concept is based on a new Nakamoto consensus algorithm using time and space to verify and validate the transactions.

Note: There is a 31-page business whitepaper released by Chia Network on March 17, 2021 that explains their philosophy and technology in more details.

Plotting

What got me intrigued and excited was really the plotting part. I spent my lazy hours reading and trying to find out more about this plotting function. Here is what I found (so far).

The plots are created by using the downloaded Chia Blockchain software. It runs on Linux, MacOS and Windows. Once installed and after the wallet creation, your computer (now called the node) will synchronize with the proprietary peer-to-peer protocol to the Chia Network, and ready to receive the mathematical puzzle challenges broadcasted in the network.

The plot creation starts with a minimum size measured in k-value. Chia recommends to start with the minimum k value of 32, and that is good enough. The plot creation uses a chunk of CPU cycles, a sizable amount of RAM (4GB to start) and also require a high speed temporary space for writing the plot. The speed of this temporary space is important because it determines how fast the plot creation can be completed. Chia recommends using an SSD for this temporary space. The plotting takes a very long time to complete before farming can begin. Gathering my experiences from the blogs, forums and chats, a plot creation using spinning drives would take 12-14 hours and with an SSD, it can take up 6-8 hours with a lot of write volume. Or even longer.

Describing the access behaviour of the temporary space, the writing process is very I/O heavy and in my educated guess, is random, small-blocks, write intensive. A workload type every storage vendor fear. At the same time, because of the very high volume of write I/Os, the wear-and-tear of the NAND Flash of SSDs amplifies quickly. Look for the TBW (Total Bytes Written) of a NAND Flash SSD for endurance and longevity.

• [ May 1, 2021 ] Mining cryptocurrency such as Chia will void your SSD warranty
• [ May 5, 2021 ] TeamGroup T-Create Expert SSD embraces hot Chia crypto craze backed by 12-year warranty

According to the latest version of 1.04, the memory and the temp space required for the plotting have been further optimized and shown in the table below:

Chia k-value memory and temp space requirements

The temp space can be reused after the finished plot has been transferred to the final destination of the farm.

Farming

While the plot creation happens in a temporary space, the final destination of the plot gets created and copied to a farm plot. The final destination should be a large capacity drive (or a sea of drives).

The farm is now ready to receive the challenges of the mathematical puzzles and perform the transactions if the hashes are most compatible to the challenges. Once transactions are completed, the farmer is rewarded with the Chia digital currency XCH or a fraction of it and is kept in the server’s wallet.

How it comes together 

This is how much I have understood so far, and I believe I am merely scratching the surface of plotting and farming. As quoted in the Chia’s FAQ:

“When the blockchain broadcasts a challenge for the next block, farmers can scan their plots to see if they have the hash that is closest to the challenge. A farmer’s probability of winning a block is the percentage of the total space that a farmer has compared to the entire network.”

TrueNAS® SCALE and Chia 

Kris Moore, iXsystems SVP of engineering sharing Chia setup on TrueNAS SCALE

[ Update: May 8, 2021 ] As I was writing this blog this morning, serendipity happened. iXsystems™ SVP, Kris Moore had just released the Chia setup walkthrough on TrueNAS® SCALE. Check out his write up.

Fast and furious. It is going to be fun.