161 lines
6.8 KiB
Markdown
161 lines
6.8 KiB
Markdown
---
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title: Mining
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sort_key: B
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---
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This document explains how to set up geth for mining. The Ethereum wiki also has a [page
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about mining](https://eth.wiki/en/fundamentals/mining), be sure to check that one as well.
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Mining is the process through which new blocks are created. Geth actually creates new
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blocks all the time, but these blocks need to be secured through proof-of-work so they
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will be accepted by other nodes. Mining is all about creating these proof-of-work values.
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The proof-of-work computation can be performed in multiple ways. Geth includes a CPU
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miner, which does mining within the geth process. We discourage using the CPU miner with
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the Ethereum mainnet. If you want to mine real ether, use GPU mining. Your best option for
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doing that is the [ethminer](https://github.com/ethereum-mining/ethminer) software.
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Always ensure your blockchain is fully synchronised with the chain before starting to
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mine, otherwise you will not be mining on the correct chain and your block rewards will
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not be valueable.
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## GPU mining
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The ethash algorithm is memory hard and in order to fit the DAG into memory, it needs
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1-2GB of RAM on each GPU. If you get `Error GPU mining. GPU memory fragmentation?` you
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don't have enough memory.
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### Installing ethminer
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To get ethminer, you need to install the ethminer binary package or build it from source.
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See <https://github.com/ethereum-mining/ethminer/#build> for the official ethminer
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build/install instructions. At the time of writing, ethminer only provides a binary for
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Microsoft Windows.
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### Using ethminer with geth
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First create an account to hold your block rewards.
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geth account new
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Follow the prompts and enter a good password. **DO NOT FORGET YOUR PASSWORD**. Also take
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note of the public Ethereum address which is printed at the end of the account creation
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process. In the following examples, we will use 0xC95767AC46EA2A9162F0734651d6cF17e5BfcF10
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as the example address.
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Now start geth and wait for it to sync the blockchain. This will take quite a while.
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geth --rpc --etherbase 0xC95767AC46EA2A9162F0734651d6cF17e5BfcF10
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Now we're ready to start mining. In a new terminal session, run ethminer and connect it to geth:
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ethminer -G -P http://127.0.0.1:8545
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`ethminer` communicates with geth on port 8545 (the default RPC port in geth). You can
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change this by giving the [`--rpcport` option](../rpc/server) to `geth`. Ethminer will find
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get on any port. You also need to set the port on `ethminer` with `-P
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http://127.0.0.1:3301`. Setting up custom ports is necessary if you want several instances
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mining on the same computer. If you are testing on a private cluster, we recommend you use
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CPU mining instead.
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If the default for `ethminer` does not work try to specify the OpenCL device with:
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`--opencl-device X` where X is 0, 1, 2, etc. When running `ethminer` with `-M`
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(benchmark), you should see something like:
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Benchmarking on platform: { "platform": "NVIDIA CUDA", "device": "GeForce GTX 750 Ti", "version": "OpenCL 1.1 CUDA" }
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Benchmarking on platform: { "platform": "Apple", "device": "Intel(R) Xeon(R) CPU E5-1620 v2 @ 3.70GHz", "version": "OpenCL 1.2 " }
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**Note** hashrate info is not available in `geth` when GPU mining. Check your hashrate
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with `ethminer`, `miner.hashrate` will always report 0.
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## CPU Mining with Geth
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When you start up your ethereum node with `geth` it is not mining by default. To start it
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in mining mode, you use the `--mine` command-line flag. The `--minerthreads` parameter can
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be used to set the number parallel mining threads (defaulting to the total number of
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processor cores).
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geth --mine --minerthreads=4
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You can also start and stop CPU mining at runtime using the
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[console](../interface/javascript-console). `miner.start` takes an optional parameter for
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the number of miner threads.
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> miner.start(8)
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true
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> miner.stop()
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true
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Note that mining for real ether only makes sense if you are in sync with the network
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(since you mine on top of the consensus block). Therefore the eth blockchain
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downloader/synchroniser will delay mining until syncing is complete, and after that mining
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automatically starts unless you cancel your intention with `miner.stop()`.
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In order to earn ether you must have your **etherbase** (or **coinbase**) address set.
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This etherbase defaults to your [primary account](../interface/managing-your-accounts). If
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you don't have an etherbase address, then `geth --mine` will not start up.
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You can set your etherbase on the command line:
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geth --etherbase '0xC95767AC46EA2A9162F0734651d6cF17e5BfcF10' --mine 2>> geth.log
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You can reset your etherbase on the console too:
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> miner.setEtherbase(eth.accounts[2])
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Note that your etherbase does not need to be an address of a local account, just an
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existing one.
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There is an option [to add extra data](../interface/javascript-console) (32 bytes only) to
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your mined blocks. By convention this is interpreted as a unicode string, so you can set
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your short vanity tag.
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> miner.setExtra("ΞTHΞЯSPHΞЯΞ")
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You can check your hashrate with [miner.hashrate](../interface/javascript-console), the
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result is in H/s (Hash operations per second).
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> eth.hashrate
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712000
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After you successfully mined some blocks, you can check the ether balance of your
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etherbase account. Now assuming your etherbase is a local account:
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> eth.getBalance(eth.coinbase).toNumber();
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'34698870000000'
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You can check which blocks are mined by a particular miner (address) with the following
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code snippet on the console:
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> function minedBlocks(lastn, addr) {
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addrs = [];
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if (!addr) {
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addr = eth.coinbase
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}
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limit = eth.blockNumber - lastn
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for (i = eth.blockNumber; i >= limit; i--) {
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if (eth.getBlock(i).miner == addr) {
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addrs.push(i)
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}
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}
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return addrs
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}
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// scans the last 1000 blocks and returns the blocknumbers of blocks mined by your coinbase
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// (more precisely blocks the mining reward for which is sent to your coinbase).
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> minedBlocks(1000, eth.coinbase)
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[352708, 352655, 352559]
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Note that it will happen often that you find a block yet it never makes it to the
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canonical chain. This means when you locally include your mined block, the current state
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will show the mining reward credited to your account, however, after a while, the better
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chain is discovered and we switch to a chain in which your block is not included and
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therefore no mining reward is credited. Therefore it is quite possible that as a miner
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monitoring their coinbase balance will find that it may fluctuate quite a bit.
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The logs show locally mined blocks confirmed after 5 blocks. At the moment you may find it
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easier and faster to generate the list of your mined blocks from these logs.
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[eth-wiki-mining]: https://github.com/ethereum/wiki/wiki/Mining
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[ethminer]: https://github.com/ethereum-mining/ethminer
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