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Viktor Trón edited this page May 17, 2015 · 48 revisions

Mining with Geth

NOTE: Ensure your blockchain is fully synchronised with the main chain before starting to mine, otherwise you will not be mining on the main chain.

When you start up your ethereum node with geth it is not mining by default. To start it in mining mode, you use the --mine command line option. The -minerthreads parameter can be used to set the number parallel mining threads (defaulting to the total number of processor cores).

geth --mine --minerthreads=4

You can also start and stop mining at runtime using the console.

> admin.miner.start()
true
> admin.miner.stop()
true

In order to earn ether through you need to have a coinbase (or etherbase) address set. This etherbase defaults to your primary account. If you got no etherbase address set, then geth --mine will not start up.

> eth.coinbase
'0x'
> admin.newAccount()
The new account will be encrypted with a passphrase.
Please enter a passphrase now.
Passphrase:
Repeat Passphrase:
'ffd25e388bf07765e6d7a00d6ae83fa750460c7e'
> eth.coinbase
'0xffd25e388bf07765e6d7a00d6ae83fa750460c7e'

Note that your coinbase does not need to be an address of a local account, just an existing one.

geth --etherbase '0xa4d8e9cae4d04b093aac82e6cd355b6b963fb7ff' --mine console 2>>geth.log

There is an option to add extra Data (up to the limit of 1Kb) to your mined blocks. By convention this is interpreted as a unicode string, so you can set your vanity tag.

admin.miner.setExtra("ΞTHΞЯSPHΞЯΞ")
...
admin.debug.printBlock(131805)
BLOCK(be465b020fdbedc4063756f0912b5a89bbb4735bd1d1df84363e05ade0195cb1): Size: 531.00 B TD: 643485290485 {
NoNonce: ee48752c3a0bfe3d85339451a5f3f411c21c8170353e450985e1faab0a9ac4cc
Header:
[
...
        Coinbase:           a4d8e9cae4d04b093aac82e6cd355b6b963fb7ff
        Number:             131805
        Extra:              ΞTHΞЯSPHΞЯΞ
...
}

You can check your hashrate with admin.miner.hashrate , the result is in H/s (Hash operations per second).

> admin.miner.hashrate()
712000

After you successfully mined some blocks, you can check the ether balance of your coinbase account. Now assuming your coinbase is a local account:

> eth.getBalance(eth.coinbase).toNumber();
'34698870000000'

In order to spend your earnings on gas to transact, you will need to have this account unlocked.

> admin.unlock(eth.coinbase)
Please enter a passphrase now.
Passphrase:
true

You can check which blocks are mined by a particlar miner (address) with the following code snippet on the console:

function minedBlocks(lastn, addr) {
  addrs = [];
  if (!addr) {
    addr = eth.coinbase
    limit = eth.blockNumber - lastn
    for (i = eth.blockNumber; i >= limit; i--) {
	if (eth.getBlock(i).miner == addr) {
	  addrs.push(i)
        }
    }
    return addrs
}
// scans the last 1000 blocks and returns the blocknumbers of blocks mined by your coinbase 
// (more precisely blocks the mining reward for which is sent to your coinbase).   
minedBlocks(1000, eth.coinbase);
//[352708, 352655, 352559]

Mining success depends on the set block difficulty. Block difficulty dynamically adjusts each block in order to regulate the network hashing power to produce a 12 second blocktime. Your chances of finding a block therefore follows from your hashrate relative to difficulty. The time you need to wait you are expected to find a block can be estimated with the following code:

INCORRECT...CHECKING

etm = eth.getBlock("latest").difficulty/admin.miner.hashrate(); // estimated time in seconds
Math.floor(etm / 3600.) + "h " + Math.floor((etm % 3600)/60) + "m " +  Math.floor(etm % 60) + "s";
// 1h 3m 30s

Given a difficulty of 3 billion, a typical CPU with 800KH/s is expected to find a block every

Mining Rewards

Note that mining 'real' Ether will start with the Frontier release. On the Olympics testnet, the Frontier pre-release, the ether mined have no value.

Transaction fees

Uncles

Ethash DAG

Ethash uses a DAG (directed acyclic graph) for the proof of work algorithm, this is generated for each epoch, i.e every 30000 blocks (100 hours). The DAG takes a long time to generate. Since the clients only generate it on demand, you may see a long wait at each epoch transition before the first block of the new epoch is found. However, the DAG only depends on block number, so it CAN and SHOULD be calculated in advance to avoid long wait at each epoch transition.

geth makedag <block number> <outputdir>

For instance geth makedag 360000 ~/.ethash. Note that ethash uses ~/.ethash (Mac/Linux) or ~/AppData/Ethash (Windows) for the DAG so that it can shared between clients.

GPU mining

Currently geth only supports a CPU miner natively. We are working on a GPU miner, but it may not be available for the Frontier release. Geth however can be used in conjunction with ethminer, using the standalone miner as workers and geth as scheduler communicating via JSON-RPC.

The C++ implementation of Ethereum (not officially released) however has a GPU miner. It can be used from eth, AlethZero (GUI) and ethMiner (the standalone miner).

You can install this via ppa on linux, brew tap on MacOS or from source.

On MacOS:

brew install cpp-ethereum --with-gpu-mining --devel

On Linux:

apt-get install cpp-ethereum

On Windows:

To mine with eth:

eth -m on -G -a <coinbase> -i -v 8 //

GPU mining with ethminer

To install ethminer from source:

cd cpp-ethereum
cmake .. -DETHASHCL=1 -DGUI=0
make -j4
make install

To set up GPU mining you need a coinbase account. It can be an account created locally or remotely.

ethminer with geth 

geth account new
geth --mine --rpc 2>> geth.log &
ethminer -G -M // -G for GPU, -M for benchmark
tail -f geth.log

ethminer communicates with geth on port 8545 (the default RPC port in geth). You can change this by giving the --rpcport option to geth.

If the default for ethminer does not work try to specify the OpenCL device with: --opencl-device 0 . When running ethminer with -M (benchmark), you should see something like:

Benchmarking on platform: { "platform": "NVIDIA CUDA", "device": "GeForce GTX 750 Ti", "version": "OpenCL 1.1 CUDA" }

or

Benchmarking on platform: { "platform": "Apple", "device": "Intel(R) Xeon(R) CPU E5-1620 v2 @ 3.70GHz", "version": "OpenCL 1.2 " }

To debug geth:

geth --mine --verbosity 6 2>> geth.log

To debug the miner:

make -DCMAKE_BUILD_TYPE=Debug -DETHASHCL=1 -DGUI=0
gdb --args ethminer -G -M

ethminer with eth 

eth -i -v 8 -j // -j for rpc
ethminer -G -M // -G for GPU, -M for benchmark
tail -f geth.log

Hardware

The algorithm is memory hard and in order to fit the DAG into memory, it needs 1-2GB of RAM on each GPU. If you get Error GPU mining. GPU memory fragmentation? you havent got enough memory.

The GPU miner is implemented in OpenCL, so AMD GPUs will be 'faster' than same-category NVIDIA GPUs.

ASICs and FPGAs are relatively inefficient and therefore discouraged.

apt-get install fglrx
// wget, tar, opencl
aticonfig --adapter=all --initial

You check your cooling status:

aticonfig --adapter=0 --od-gettemperature

Further Resources:

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