The miner decided to share his story anonymously.

Mining Epidemic

Today we are in the middle of the coronavirus outbreak, and once there was a mining epidemic. Mining epidemics, to be precise. The biggest one happened in 2017. What provokes such epidemics? Of course, it’s the growth of cryptocurrencies in value. 2017 was no exception. In spring 2017 Bitcoin grew from $1,000 to $3,000, and Ethereum grew even more. It leaped from $10 to $300.

Suddenly, mining became an extremely profitable business. Everybody talked about it. Literally every one. The Internet was exploding.

What is mining? How to mine? I didn’t know anything. I called my friends and they didn’t know anything either. So I decided to try mining on my own.

For those who are far from the mining industry, I will specify that in 2017 it was already impossible to mine Bitcoin using anything but special ASIC miners. At the same time, you could and still can mine Ethereum using GPUs. That’s right, the same graphics cards that you use to play League of Legends, Grand Theft Auto V or Fortnite.

First Mining Rig

ASICs were hard to choose. I had no idea how they work and was not convinced by the photos on the Internet. They looked like those typical “Made in China” devices of poor quality. I decided to opt for GPU mining. Several graphics cards, usually six or eight, are combined to form a single computer/rig. And you are good to go. Here comes the first problem. Graphics cards cost way too much. The mining epidemic caused an increase in prices by at least two times.

I somehow managed to get eight Nvidia 1070 graphics cards, paying $400 for each, and began to build my first rig. What a nightmare it was. Now there are more resources, like 2Miners Blog 🙂 but in the past, you had to read those awful forums and gather information bit by bit.

Luckily, I knew how to build a computer, so I didn’t have problems with installing a processor into a motherboard or installing Windows OS. So I finished my first rig. I just had to setup BIOS, changing settings this and that way, until Windows finally detected all of my eight graphics cards. I should say that changing BIOS settings to make eight graphics cards work on Windows was a real adventure. I downloaded the mining software. Now I had to get a wallet.

Ethereum Wallet

What would any sane person do? Google “Ethereum”, go to the official website and download a cryptocurrency wallet. That’s what I did. I launched the wallet and was asked to wait. It said that I needed to synchronize blocks. So I did that.

By the way, the rig wasn’t working, because I didn’t have a wallet yet.

I went to work, and when I came back in the evening, the synchronization wasn’t over yet. The wallet took up the enormous amount of my computer memory. I found a way to close the sync window, and only then I found out that I could simply copy my wallet address without waiting for the whole blockchain to load. So I copied the address. I added the wallet address to the mining program, and the process started. I put the rig in the hall so that it didn’t disturb my sleep.

When I woke up, I checked the wallet and saw that the synchronization was still going on. I decided to Google the problem. They said that a regular hard disc wouldn’t do and you needed an SSD. Forums advised getting Jaxx, a multi-token wallet. Instead of storing a blockchain on the computer, the wallet stores it somewhere on its own server. Paranoid as I am, I didn’t like it. But I had no choice. I wanted those precious coins on my wallet so bad. I downloaded and installed the wallet, copied the address, reconfigured the miner. And then I went out. When I came back in the evening and opened the wallet, I saw something. Success!

I was so excited. So I said to my wife: “Open that bottle of red wine from the birthday party. Let’s celebrate!” “What an idiot,” she thought, “Keeps this damn noisy thing in our apartment and is so happy about it!”

Too Late to Start Mining

One week passed without any problem. I was regularly getting Ether on my wallet. I calculated expenses on electricity and discovered that the rig was bringing me $10 per day. So it was supposed to pay off in one year. I knew well that cryptocurrency exchange rates are extremely unstable, but at that point, I couldn’t be stopped.

I was making money out of air. Every single day. And most importantly, a pay-off period was just one year. Where else could you find anything like this?

Now, sorry if I say something stupid in terms of economics, but who would offer you a 100% annual interest rate? I was convinced that nobody would. On the Internet people were saying that soon it would be over, it was too late to start mining, only those who started a year ago were making money, etc. But I was unstoppable.

I started looking for cheap graphics cards because I didn’t want to overpay. Motherboards, PSUs and other parts were easier to find because they were always available in regular shops. Sometimes risers that I wanted were out of stock, so I had to buy poor-quality models. A month later, I already had five mining rigs in my apartment, and I was making $60 per day. At that point, there were rigs not only in the hall but literally everywhere.

For the night I put them in the hall and in the kitchen with the window wide open. Otherwise, it was impossible to sleep because of the heat and the noise.

One day I woke up at night to go to the bathroom, but then I stopped in the hall. I smelled something electrical burning. I thought they were my rigs, but then I realized that the problem was somewhere else. The wire going into my apartment was hot as hell, and the plastic around it was melting off. I quickly turned off the rigs. I was glad I didn’t burn anything. But I couldn’t go on like this. It was time to find a place for my rigs.

Mining Equipment Room

Yes, I needed to build an equipment room. What other choice did I have? I couldn’t say to a landlord that I wanted to mine cryptocurrency. So I called factories and industrial areas explaining that I needed space for a small data center (server room). Preferably with a window and 20 kW of power. I opted for old factories because I thought they would have fewer problems with power.

A week later I found the space and relocated my rigs there. The room was small, 15–20 square meters, but with two large windows that I had to open right away to cool down my rigs. Otherwise, everything was heating up badly, and keeping the door open was not an option. What if someone would steal my cards?

That’s how I started a large-scale mining business. Just joking. People put the billions worth of equipment right next to power stations. And I was not even close.

First ASIC Miner

I built a couple of new rigs, but I wanted more. I was really curious to try ASIC mining. Besides, it’s best to diversify. What if Ethereum mining died? Bitcoin, on the other hand, had been around for almost ten years. I decided to try.

I bought my first ASIC and launched it. I can’t even describe how much noise it was making. Good thing I didn’t keep it at home. It would have been unbearable for me and my neighbors. ASIC setup was super easy. I just added the mining pool address, my wallet, and that was it. Much easier than with rigs. A pay-off period was less than a year.

“Wow, this thing really works,” I thought, “I need to get more.”

More Mining Equipment. Transition to Linux OS

I built a few more rigs and ordered different ASICs from China. Antminer L3+ to mine Litecoin, Antminer S9 to mine Bitcoin, and Antminer D3 to mine Dash. I also bought Antminer A3 for SIA, but it happened a year later.

At that point, I had both Nvidia and AMD rigs. Sadly, to make AMD cards mine correctly, I had to upgrade each card separately. Upgrades (timings) were not always easy to find. And even after upgrading I had to spend a lot of time to configure GPU overclocking in Afterburner so that a graphics card gave out a maximum hash rate. Moreover, AMD cards heated everything ten times as much as Nvidia cards. It depended on the model of course, but generally, they were super hot. Devil, for example.

I couldn’t control my rigs anymore. There were constant errors, GPU bugs, unexpected Windows updates. Then TeamViewer suspected commercial use and limited my connection time to five minutes. And then I had to wait for ten minutes. Instead of having dinner with my wife, I had to go to my equipment room and reinstall an operating system.

I installed Linux on all of my rigs. The first installation took me some time, but I did the rest pretty fast. I was sorry I hadn’t done it earlier. It was so simple. Online monitoring for just a couple of dollars a month for each rig.

Okay, now let’s end the boring part. Everybody wants juicy details.

How Much Money I Could Have Made with Mining

I could have made tons of money. Did I make tons of money? Rather no than yes. Because I made a lot of mistakes. But they do say that you learn from your mistakes, right?

How much money did I spend on mining equipment? 200 thousand dollars. That’s right, I could have used that money to buy a nice apartment.

How much money could I have made? No less than 400 thousand dollars. I could have recouped the cost of equipment and earned as much on top.

What mistakes did I make? Why did I earn much less?

Mistake One. I wasn’t selling cryptocurrency.

What is mining? Mining is the process of getting a reward for calculations. You buy hardware with the purpose of making money, real dollars. You must make them every day.

I wasn’t selling my cryptocurrency because my living conditions allowed me to do so. Exchange rates were constantly going up. So I held my cryptocurrency. My savings were growing by leaps and bounds. I was dreaming of buying one Tesla, then another one. Suddenly, all went down. In spring 2018 Bitcoin and other cryptocurrencies fell even more.

A year later I hoped that Bitcoin would go up, but it didn’t happen. I was losing money every day at the same pace I was earning it in 2017. I didn’t want to sell Bitcoin for $10,000. Not so long ago it was valued at $20,000. Selling for $8,000 was just foolish. I was sure it would grow soon. Then it went down to 3 thousand. At that point, there was nothing left to sell. I was trapped.

Conclusion: Once you get cryptocurrency, sell it.

Mistake Two. I started investing.

I was actively trading my Ether and building my cryptocurrency portfolio. I had never traded in the stock market, and this was a new niche, exciting and unknown. I was researching cryptocurrency projects and buying their cryptocurrency or tokens. I invested in ICOs. One ICO brought me twice as much, another one – three times as much.

Wow, I was born to be an investor!

Later I realized that anyone could be outstanding in the rapidly growing market. Even the worst investor would gain profit. But then I fell so bad.

After a year and a half of my cryptocurrency adventure, by the end of 2018, I realized that there is only one coin that rules. It’s Bitcoin. Others are just rip-offs. Okay, maybe Ether is also fine. But that’s it.

Conclusion: Mining and investment are not the same things.
You can’t do it all. You can either mine or gamble on the exchange. Everyone must do their own thing. In order to gamble on the exchange, you don’t have to mine, and vice versa. In order to mine, you don’t have to be an investor.

Mistake Three. I was mining shitcoins.

Euphoria is a dangerous thing. In 2017–2018 cryptocurrency projects were growing by leaps and bounds. I was getting bored, so I was always searching for something new. There were a lot of new coins to choose from. Those who were good at programming copied Ethereum or Bitcoin, changing a few words in the code or even leaving it as is.

The same wallet, the same infrastructure. They changed only a logo. I mined a lot of coins. WhaleCoin, PegasCoin, Musicoin, just to name a few.

I held everything. Sometimes I waited for an exchange to add a new coin and sold at once. I was making a good profit. I was happy back then, but now I realize that I could have made much more money if I had mined Ethereum.

Conclusion: Mine liquid coins that are easy to sell.
If you are willing to mine something new, exchange it for something decent (Bitcoin) at once or sell it for fiat money (dollars).

Mistake Four. I was greedy and careless.

Bitcoin hard forks were happening all the time. Every month there was a new fork – Bitcoin Cash, Bitcoin Gold, etc. And every time I wanted to get new coins. I was curious.

When Bitcoin Gold (BTG) was launched, there was a lot of hype around it. The launch price was $300, if I remember correctly. Everyone was looking forward to it, including myself. I wanted to see how many BTG coins I could get. I just needed to enter the private key to my wallet on the “official” Bitcoin Gold page. I entered the key. And I saw how much I would get.

Now I realize that I was such a fool, but back then I had no clue. As you might have guessed, I didn’t see bitcoins on this wallet ever again. Neither BTG, nor BTC. I was smart enough to use the empty wallet on the BTG website, but later I got a payment on it. And of course, I didn’t see it.

How much did I lose? A whole lot, much more than 1 BTC. I don’t remember exactly. I just try not to think about it.

Conclusion: Keep the private key to your wallet safe and don’t show it to anyone.

Mistake Five. I kept money on crypto exchanges.

This one is obvious. Everybody knows it, from Andreas Antonopoulos to a fifth-grader. Just don’t keep your coins on exchanges. Create a wallet, exchange cryptocurrency and transfer your coins out. This is the only possible way. An exchange may close sooner or later. It happened to a few exchanges. The case of Cryptopia was the most sensational. I didn’t lose much on this exchange, I think it was Pirl. I see that now there are still those who mine it. I wonder why.

Same thing with Nicehash. It is a platform that rents mining power. My ASICs worked through it for a while. The coins were stored on the Bitcoin wallet on Nicehash. Suddenly, Nicehash crashed. The money of all the users was stolen. The company apologized and came up with a program to compensate its clients. They compensated a little over 80%.

How much did I lose? A whole lot, around 0.5 BTC.

Conclusion: Don’t keep money on cryptocurrency exchanges.

Mistake Six. I lost control over my hardware.

I had as many as two incidents. The first one is as follows. A friend of a friend of a friend offered me to buy mining rigs in the place with cheap electricity. Not just rigs, but hosting as well. They sell you mining rigs and promise to keep them in the special room equipped for mining and maintain them. You pay only for electricity. Because I somewhat knew the seller, I decided to go for it.

For a few months it was going well, then the problems started. At times there was no electricity, then he had to move the rigs to a different place, and so on. So I told him to return my rigs. I barely managed to get back half of them.

The second incident happened in 2018. ASICs were slowly losing momentum. A friend of a friend offered to keep my rigs. I was supposed to pay $0.01 per kWh. I said yes, because the rigs were not bringing profit at my place. This time I decided to be smarter. I sent only Antminer D3 that had no value to me. Why? You’ll find out in the next chapter. I sent my ASICs and never heard from the man ever again.

Conclusion: Don’t trust anybody. This is the harsh reality of life.

Mistake Seven. I didn’t know how to choose mining hardware.

Today everybody is smart. Back then I was randomly buying ASICs available on Bitmain. Antminer D3 worked for only a month and a half. Mining difficulty increased instantly. Profitability was close to zero. Antminer A3 lasted even less. Maybe for a week. At the time when it was delivered, it had already become obsolete. I didn’t want to pay the rest of the sum for it, but as it had already arrived, I felt bad. Besides, I already paid the bigger part when placing an order.

You don’t necessarily have to buy expensive graphics cards. Nvidia 1060 and 1050Ti perform quite well, and you may also consider getting pre-owned graphics cards or mining rigs, if they can be checked. Many wanted to recoup money by selling their rigs cheaply. I had the chance to make a good deal, and I did so a couple of times.

Conclusion: Choose mining hardware wisely. Do your own calculations.
Don’t put warranty in the first place. During my years as a miner, I changed only two graphics cards on a warranty, and both were defective from the beginning. Graphics cards can work for years without maintenance.

End of Mining

Everything inevitably comes to an end. My mining business is no exception. Sadly, considering current exchange rates, an electricity price for industrial consumers in my country ($0.06–$0.07 per kWh), associated costs (a rent, equipment maintenance, the replacement of faulty parts), I barely make any profit.

I turned off my last ASICs at the beginning of 2019. Antminer S9 devices worked longer than others. Then they were just standing there. I have no idea what to do with them. For now, they are just cluttering my garage. I am trying to sell them. ASICs lost 90–95% in value, but I can’t sell them even for 5–10% of the original price. There is no demand.

I turned off my GPU rigs in January 2020. Profitability reached zero. I was surprised that I managed to sell almost all graphics cards individually at a good price. I think graphics cards lost 50% in value. So you can sell them for half of the original price. I used the cheapest motherboards, RAM and processors, so they were impossible to sell. I was lucky to sell at least some of the parts as a set for about $20.

So how much money do I have left?

As I mentioned earlier, I spent $200,000. I recovered around $150,000. I plan to sell $50,000 worth of graphics cards. I have around $40,000 in Bitcoin. I decided to hold this sum in Bitcoin and see what will happen in five or ten years. Who knows, I may buy a house somewhere in Miami one day. Or I may lose everything.

But I have nothing to worry about. I didn’t lose any money. Again, if I had been smarter, I could have easily made two times more money.

Future of Mining

The King is dead. Long live the King!

Mining is not dead. Today mining is a large-scale business run by professionals. Objectively, mining is a profitable business. But in 2017 it was profitable for everyone. In 2018 countries with expensive electricity dropped out. In 2019 everybody else dropped out. In 2020 you can mine only if you have cheap electricity. Mostly it’s China and Russia.

Everybody knows that the electricity price in Irkutsk is $0.013 per kWh. But I don’t want to go there and organize mining. It won’t work without supervision. Some put enormous rigs right next to power stations and use electricity basically for free, but we are talking about large-scale businesses. Others steal electricity, which is definitely not for me. Miners believe in karma. Bad guys don’t get blocks.

Mining from Home

What about mining from home?

Fair question. Mining from home is very much alive. In Russia, for example, the average electricity price is around $0.03–$0.04 per kWh. You can make a good profit by keeping a few rigs at home. If you build a rig using regular PSUs for desktop computers rather than server PSUs (that’s what miners often do to save money), rigs won’t make almost any noise. As if you had a regular desktop computer running 24/7. Each rig consumes 1 kWh, that is, a little less than an electric kettle. Wiring in most buildings should easily handle a few extra kilowatts. But this is not financial advice so think with your own head. If your wiring burns, it won’t be my fault. Make sure to check everything beforehand.

As for me, I could have left a few rigs at home, but honestly, I lost interest. In the past I was always in search of the most profitable coins for mining, there was always something new to explore. And what now? You just have to setup Ether mining and forget about your rigs for a year. Boring. Plus, I have a dog now, and I have no wish to remove fur from the GPU coolers every week. If nobody buys my graphics cards, I will build a rig and use it to heat my garage or my parents’ country house in winter. I’m sure it heats better than a regular radiator.

I would like to thank everyone who has made it to the end, as well as the 2Miners blog editors for letting me pour it all out and for your work. When somebody asks me about cryptocurrencies, I always share the link to your blog. I also thank the 2Miners pool itself. You have the best interface, you taught me how to mine Solo, and your Telegram chat is the best mining chat ever.

MAKE SURE TO FOLLOW US ON TWITTER

Nervos CKB Mining

Nervos CKB mining on the 2Miners pool started right after the launch of the main net in mid-November. Mining was going well, and the coin often ranked first by profitability, according to 2CryptoCalc. Since it was the most profitable coin, users were actively mining it.

At that time the coin even ranked third in SOLO on the 2Miners pool. And today the three most popular coins among miners are Ethereum Classic, Ethereum, and Bitcoin Gold.

In order to mine Nervos CKB, you need Nvidia or AMD graphics cards. As for the software, we recommend Gminer – we already mentioned it in our mining tutorial. Basically, anyone could make a decent profit from this coin. This ensured the safety of the network – the overall hash rate was provided by a great number of graphics cards located in different parts of the world. This is what decentralization looks like.

Nervos CKB Hashrate Issues

But now everything has changed. Since the hash rate increased ten-fold, it has become more difficult to mine CKB. And the profits went down. On November 19, 2019, three hundred Nvidia 1070Ti graphics cards were bringing $410 per day on Nervos CKB. Today it is much worse. According to 2CryptoCalc, today the same graphics cards would be bringing $4.46 per day.

Only two weeks ago profitability was ten times higher because the hash rate at the beginning of the month was much lower. Check the Nervos CKB Hashrate chart.

Why Has Nervos CKB Hash Rate Increased?

It is a rule that ASICs or FPGA’s are to blame for a sudden increase in the hash rate. Since ASICs are specifically designed to mine a certain algorithm, their mining performance is better than that of GPUs. They have a significantly higher hash rate – accordingly, they also have higher profitability.

This time Antminer K5 by Bitmain, that we first heard of at the beginning of March, may be responsible for the changes in the network performance. It is an ASIC for Eaglesong – the very algorithm on which Nervos CKB works. Its hash rate is 1.13 TH/s, and the consumption is 1580 W. By comparison, 300 Nvidia 1070Ti GPUs give out 0.22 TH/s. 2CryptoCalc confirms this information.

But Antminer K5 is not yet available to regular users. We have checked it: now it is listed on the Chinese version of the Bitmain website, but sales are planned to start in the first half of April. Here are the specs.

Even the WhatToMine calculator states that the miner is not available yet.

By the way, note the estimated profitability. $18.21 daily per miner at the electricity cost of $0.05 is 4.6 times higher than the profitability of 300 Nvidia 1070Ti GPUs. This is crazy.

Just a week ago the profit was as high as $200 per miner. In the 2Miners Telegram chat users were asking whether to buy this device. Clearly, the profitability will keep going down.

It seems that the first batches of ASICs are ready and being “tested” right now. This is one of the biggest known faults of ASICs. Sadly, nothing can be done about it. The devices are in the hands of the manufacturers, so they decide when to start shipping.

Why Nervos Developers Stay Silent

The silence of the Nervos CKB team seems especially strange. We checked their Twitter posts in March, and they don’t mention a sudden increase in the network hash rate or how to solve this problem. But they do announce collaborations, presentations, and listings on different platforms.

Why is it a problem? As mentioned above, the Nervos network hash rate has increased ten-fold since the beginning of March. It is likely that new Bitmain monsters are behind it. In this case, these ASICs account for 90% of the network. They are probably not interested in organizing a 51% attack – they are just making money. But this goes against the principles of decentralization in the crypto industry. The network must be supported by miners in different parts of the world rather than by one factory. And with much less power.

Nervos could follow Grin’s example – its developers performed a hard fork in June that secured the network against ASICs. Grin developers are constantly making changes into the mining algorithm to discourage manufacturers from making ASICs. After all, creating a new model every six months and throwing away the previous one is not the most profitable business. However, Nervos developers have never claimed their algorithm to be ASIC-resistant.

2Miners Has Decreased the Minimum Payout

The minimum payout for Nervos mining was always 500 CKB ($1.7). We realize that many Nervos CKB miners were forced to leave the pool due to the increased mining difficulty. For this reason, today (March, 21) we are performing the one-time payout for all the miners whose balance has reached 100 CKB (5 times less than the standard payout threshold).

Update. Toddminer C1 for Nervos CKB

We’ve just received the information from our miners that they have already received the new Todek Toddminer C1 for Eaglesong mining algorithm.

Toddminer C1 hashrate is 1.55 TH/s, and the consumption is 1380 W. The specifications are even better than Antminer K5. Both Antminer K5 and Toddminer C1 could be the cause of the sudden Nervos CKB hashrate increase in the past days.

What to Mine With GPU’s?

Sadly, today Nervos is not the best cryptocurrency for GPU mining. According to 2CryptoCalc, the best coins for mining today are ZClassic, ZCoin, and ZelCash.

We hope that Nervos developers will soon take the situation under control and CKB will regain its top position among the most profitable cryptocurrencies for mining. When mining profitability experiences such a drastic drop, developers must interfere. Otherwise, miners would turn away from the project and start mining other coins.

How to Choose a Wallet for Grin

GRIN crypto network has always had a problem with wallets. Sadly, the developers don’t have their own GUI wallet. Neither for desktop PCs nor for mobile devices. If you want your coins to be as safe as possible, you must opt for a wallet with a command line (that is, without visual interface), learn commands and so on. For an average user, this is a nightmare. There is also an open source grin++ wallet, but it is not compatible with all wallet versions.

In order to perform a transaction in GRIN, wallet versions must coincide. If one user has a new version, while the other has an older version, it is unlikely that the transaction will go through.

As a mining pool, we must always choose the wallet version that works with as many other wallets as possible. Usually, we strongly recommend not to store coins on crypto exchanges. However, in the case of mining GRIN, we recommend to use addresses generated by crypto exchanges. Why is it so?

In the case of GRIN, both sending and receiving wallets must be online at the moment of transaction, otherwise, it will not go through. Most cryptocurrencies allow you to simply send coins to a certain address. And it doesn’t matter whether a user is online or whether he has a private key from this wallet. You can send coins abroad to a complete stranger even if he didn’t ask for it.

2Miners Pool Payout System

2Miners payouts are automatic. As soon as a miner reaches the minimum payout, the coins will be transferred to his address. The amount differs from coin to coin. For GRIN it is 3 coins.

Then in the course of two hours, the pool sends the reward. The system is fail-proof. The exception is BEAM and GRIN cryptocurrencies, where both sending and receiving wallets must be online. If a receiving wallet is offline, the pool will try to send the reward every two hours until it succeeds.

Recommended Cryptocurrency Exchanges

Every cryptocurrency on 2Miners pool has a page with settings where we also list recommended wallets and crypto exchanges. Again, we don’t recommend using exchanges to store funds, but many of our users still like it. As a pool, we can easily send payouts to any type of wallet. I doesn’t matter who owns the wallet, a miner or an exchange, that is not our business.

How do we choose which exchanges to recommend? First of all, nobody pays us for placement on the assistance pages mentioned above. We choose top-rated exchanges. We test platforms personally and if they work properly, we list them. We are not responsible for neither hardware wallets nor exchanges. Their developers are responsible for them. But we do take responsibility for our work because we value our reputation.

As they said at the beginning of GTA2: “And remember, respect is everything”.

GRIN has a long list of recommended exchanges. It’s because not all crypto exchanges support the automatic reception of GRIN coins, so we made sure to list all compatible exchanges. When GRIN was launched, there were only two such exchanges, then there were eight. It doesn’t mean that we personally like all of them. We just tested them and notified our miners that they work properly.

Transactions in GRIN Network

GRIN is a safe and “hidden” blockchain. GRIN doesn’t have a so-called blockchain explorer that provides information about the network operation. Transactions are hidden from unwanted eyes. Only the sender and the recipient can check whether the transaction went through (provided they have a transaction ID).

Cryptocurrencies don’t have customer support or “cyber police”. It means that if your funds were stolen or you sent a transaction to the wrong address, no one would be able to help. In traditional blockchains like Bitcoin or Ethereum you can always go to the blockchain explorer and find out who is right and who is wrong. You will see who received coins, how many, from which address and when.

So let’s take another look at the two main features of transactions in GRIN:

1. A receiving wallet must be online for the transaction to go through.
2. There are no blockchain explorers. It is impossible to check whether someone’s transaction was really performed.

Bitforex Issue

On January 9, 2020 the pool sent 59.08800 Grin to the Bitforex exchange address as a reward to the miner. Transaction ID (Txid) is 11476547-b7ee-4531-7adc651dee0c. The funds haven’t reached the exchange. We always try to help our users, so we contacted the exchange.

First, we tried to find out what happened through the official Bitforex Telegram channel. We got in contact with administrator Kate. Honestly, her answers were embarrassing. It was clear that she was completely incompetent in the matter. We have tried a few times to find contact information of senior managers, but every time we were refused with an inconclusive reply.

1. Here she tells us that the transaction was 4 GRIN instead of 59.08800 GRIN and attached the following screenshot.

   

   After a simple comparison of transaction IDs, it becomes clear that this is not the transaction we were asking about.

2. Then she tells us that on January 8 Grin deposit was closed for one day. First of all, the transaction we are talking about was not performed on January 8, but on January 9. Second, the transaction can’t go through if the receiving wallet is offline. You can’t send coins into thin air. If it were possible, we wouldn’t have a TX ID.
3. 3. And here is the funniest response of all. Quote: “Hello, unfortunately, we haven’t received this transaction, we can’t find it in our system, so the coins can’t be transferred. Screenshot is attached.”

   

   Why is it so funny? Because we already sent this very screenshot to her. Previously a 2Miners employee sent this screenshot from our wallet. She saved it and then sent it to another 2Miners employee as if it were a screenshot from the Bitforex exchange wallet.

   That’s right, the exchange employee saved our screenshot and resent it to us as proof making it seem like it was sent by the tech department.

   Our discussion ended with the following quote.
   I am sorry that you were not able to get in contact with the team. I am sorry for the user, I really did everything I could, my only responsibility is to quickly pass information to the tech department. And over the course of a long period of my work this is the first time when coins are not transferred. If the coins were sent successfully, the exchange would transfer them to the user with a probability of 1000%. I am sorry, but I don’t have access to any technical details.

   

   As a rule, exchanges always manage to find coins that belong to users and in case of a problem they transfer them provided you have a TX ID. On the contrary, the employees of the platform refused to do so saying that they didn’t receive any coins.

   So we thought that maybe it was just a misunderstanding caused by incompetent employees, translation difficulties, etc. We decided to try again. We wrote to support@bitforex.com – the official tech support. Six days with no answer. Nothing at all.

   Then we wrote to the official tech support through their helpdesk. Five days – no answer. We only got an automatic notification that our message had been received. But it was all in vain.

   Who Is to Blame and What Is Next?

   The answer is simple – we don’t recommend using Bitforex exchange. If the exchange can’t admit its fault and can’t reply to the message for five days, and the administrators of the exchange chat write complete nonsense, then you can’t trust your funds to such a platform.

   We have deleted Bitforex from all recommendations on 2Miners pool. It is not about money, it’s about professionalism and respect to clients. Our miner has spent one month trying to solve the problem, but hasn’t received any feedback. Same happened to us.

   We took this problem to heart. We decided to pay to our miner 59.08800 GRIN lost by Bitforex exchange from our own funds. Unlike Bitforex, we value our reputation.

   MAKE SURE TO FOLLOW US ON TWITTER

MOAC Delisting

We’ve stopped MOAC pools on February 3rd due to the network problems. All the situation was covered in our post MOAC Network is Under Attack. We’ve observed multiple denial-of-service attacks on the network. Blockchain was split many times. Unfortunately, MOAC blockchain developers have done nothing in nearly one month so we have decided to delist MOAC coin from the pool.

2CryptoCalc Mining Calculator Updates

Mining Profitability Calculator 2CryptoCalc is becoming better everyday. This month we’ve added such features:

• GPU Memory check. If GPU is not able to mine a specific coin, this coin is not shown in the list;
• Specific GPU and algorithm pages;

We are working on GPU ranking page, new design and many more awesome features.

2Miners Pool Monitoring System

Our CTO Erik Van Daal has written amazing post Monitoring for Health. He thoroughly explains many problems encountered by the mining pools and how do we monitor them. Blockchain splits, DDOS attacks, Orphan blocks and more problems are described in this article.

Antminer E3 Problem

Very popular Ethash ASIC miner Antminer E3 has stopped mining Ethereum Classic this month. It will stop mining Ethereum in April. This has happened due to the ASIC memory limit. Antminer E3 can not store the constantly growing DAG file anymore. Read more in our post Antminer E3 Stops Mining Ethereum Classic, Just Over a Month Remaining for Ethereum.

Innosilicon A10 Specs and Setup

We’ve successfully tested newly-built Innosilicon A10 ASIC machines. We’ve upgraded our pools to support these devices.

Innosilicon A10 is 2 times more effective than previously available ASIC’s and GPU mining rigs. It consumes 750W providing 500MH/s hashrate on Ethash mining algorithm. Check Innosilicon A10 Specs, Profitability and Setup Guide.

Nicehash and ASIC Stratum Protocol Updates

We have updated our pools to support native NiceHash and ASIC-compatible Stratum protocols. This allows our miners to be more efficient both using Nicehash rented hashpower and ASIC’s. Why is this important? Read here NiceHash and ASIC-compatible Stratum Protocols on 2Miners.

MAKE SURE TO FOLLOW US ON TWITTER

What Is a Mining Pool

As you may know, 2Miners are a quite intensive operation: we have almost 40 pools, most of which are specialized software on dedicated physical servers located in three locations around the world.

A moment of clarification: each pool is a combination of four essential components:

1. A cryptocurrency node that hosts the blockchain, submits new blocks found by the pool miners to the network and processes the payouts to the miners.
2. The specialized custom-written pool software that accepts and verifies miner solutions, distributes new computing work and analyzes miner statistics.
3. A high-performance database that accumulates all submitted shares, stores the miner-related statistics and every other relevant data.
4. The Web frontend displays the miner data, graphs, payout history and so on.

As you may guess, any of these four components can face different problems and if any of those fails, it will affect the operation of the pool. How the Mining Pool Works: PPLNS vs. SOLO.

Most Common Mining Pool Problems

The way cryptocurrencies work is by no means error-prone and all kinds of bad situations may occur. Here are the most common ones that we face more or less on a regular basis:

• There is a network split causing the cryptocurrency node to mine on a wrong chain causing rejected blocks and the loss of profit for our miners;
• Due to some bug in the cryptocurrency node the mining process is affected or interrupted;
• There are issues with the network connection between our servers in different data centers around the world (we currently host our servers in Europe, Asia, and America);
• There is a DDoS attack running against our servers by some malicious attackers who try to disrupt the operations;
• The disk or RAM space on one of our servers is low or there is a hardware component fault so there is a risk of losing some data;
• A ghost of Vitalik Buterin is trying to steal some blocks from our ETH pool (okay, just kidding about this one).

We have designated people that are reacting to threats and incidents 24/7/365. But how do those specialists know there’s a problem that needs to be solved?

Enter the Telegram. We use it extensively for our work-related chats, including problem monitoring. Specialized custom-developed bots watch every aspect of day-to-day pools operation and report to us any problems and irregularities. Not every warning means a real problem, so the DevOps team carefully checks each message and reacts to the ones that need attention.

What stuff do we actually monitor? Let me describe in more detail which aspects of the pools are being watched.

Zabbix Monitoring

Zabbix is an open-source powerful monitoring system that can be extended by custom plugins to watch over some custom aspects of each machine we have in operation. Zabbix watches the disk space, CPU and RAM usage, current traffic and network load, the health status of our web frontends and microservices. Also, we have a set of custom plugins that watch over the availability of mining ports, mining luck, and payment issues.

Each incident is tunneled over to a special private Telegram chat and then analyzed and acted upon, if needed.

It is worth noting that we try to keep the CPU load of our servers below 20% to allow for unexpected short spikes in usage and to provide a good mining experience for all of our users. If there is a steady increase in the CPU load that is not going away, it is a good reason to enable backup hardware infrastructure to mitigate the load.

Orphan Blocks Monitoring

Some Ethereum-based cryptocurrencies have a mechanism called “Orphans” for blocks that were mined with the correct solution, but the blockchain network has chosen to pick some other block mined by some other miner or pool because it was mined a few seconds earlier or so; the orphans are usually also rewarded but in smaller amounts. You could find more information on that in our post Orphan, Stale & Uncle Blocks in Bitcoin and Ethereum. In Bitcoin world, term “orphan” is usually used to indicate blocks that have a correct solution, but that were not accepted onto the main blockchain for various reasons (mined later than somebody else, or mined onto an orphaned chain); these are not rewarded.

Either way, an orphan appearing is a reason to do a quick check: are the nodes healthy or they are in the early stages of a split? Is network connectivity stable enough so the solutions are delivered to the rest of the blockchain network as fast as possible?

Blockchain Split Monitoring

So-called “network splits” happen when some network nodes disconnect from each other and start producing a distinct chain of blocks. Once they reconnect, the blockchain chooses one of the chains, making the entire another chain invalid (or orphaned). This is potentially bad for our miners as it means a potential loss of profit. This is why we try to detect these situations as early as possible and try to eliminate them. Chain split could happen accidentally or it could also be a result of a 51% attack.

A special monitoring bot takes various sources of information (our own nodes, some well-known explorers on the Web, some other pools’ data, etc) and estimates whether our cryptocurrency nodes are in the correct chain or not. If not, an alert is emitted so our engineers can verify it. It is worth mentioning that an official coin explorer can often be itself in a split, so we trust pools’ data more (after all, it’s the source of new blocks so they often have more accurate information).

Other Emergency Mining Pool Monitoring

The error conditions above are not nearly the exhaustive list of what can go wrong with a cryptocurrency mining pool. There are lots of times when due to programming bugs the cryptocurrency nodes report an error and stop working, requiring a restart. All of these cases are handled by a separate bot. So whenever something that’s not in the predefined list goes wrong, this bot will pick it up and report to the DevOps team. Then some issues are as easy as “restart the node”, and some require some thoughtful investigation sometimes resulting in a bug report to the cryptocurrency maintainers or even a pull request to fix the bug.

Miner’s Monitor

Last but not least, while all of the things mentioned above are private and used internally, we do have a Telegram bot that’s accessible for any miner: @Pool2MinersBot. It is quite a powerful bot that latches on the same backend as our internal tooling. Not only can it report to you whether one or more of the workers has gone online or offline, but it also notifies when your worker finds a block and provides a useful source of information for the statistics of your mining operations.

I believe a professional and well-thought process of monitoring existing resources is key to a successful mining pool business. While almost anyone with mediocre programming background could assemble a simple pool using the open-source software, making it handle a big load and do so in a performant manner, while watching for all the issues a pool may have, takes a team of highly skilled professionals, just like with anything else. We at 2Miners care about our users as our own income depends on how well we do so.

That’s it for now. Peace!

MAKE SURE TO FOLLOW US ON TWITTER