Frequently Asked Questions - Wiki OpenEthereum Documentation


Most asked questions

How to get OpenEthereum in sync quickly?

The quickest way of syncing OpenEthereum client with the top of the chain is achieved using Warp Sync in combination with warp-barrier.

To make sure you get the most recent snapshot available and warp sync very close to the top of the chain, OpenEthereum supports the flag --warp-barrier [NUM]. Replace [NUM] with the chain’s latest block number minus at least 10,000 blocks. Example: if latest block number is 5,633,123 you should launch openethereum --warp-barrier 5620000.

Read more about Warp Sync.

What are the OpenEthereum disk space needs and overall hardware requirements?

Running a node with the standard configuration for the Ethereum Mainnet requires a lot of computer resources. The blockchain download and validation process are particularly heavy on CPU and disk IO. It is therefore recommended to run a full node on a computer with multi-core CPU, 8GB RAM and an SSD drive and at least 400GB free space. Internet connection can also be a limiting factor. A decent DSL connection is required.

Node performance can also be improved significantly by using OpenEthereum’s caching features, and accessing state from memory instead of from your disk by specifying the --cache-size flag - optimally this requires you to have additional RAM equivalent to the state size of the blockchain you are connected to, over 8GB on Ethereum mainnet, for a total of over 12GB of RAM.

Storage Requirements Overview

Indicative data storage requirement from December 2018 syncing Ethereum Mainnet with OpenEthereum 2.2.4:

Client / Mode                  | Block Number   | Disk Space | CLI flags                    |
openethereum +warp -ancient    |      6_850_000 |        29G | --no-ancient-blocks          |
openethereum +warp             |      6_850_000 |       133G |                              |
openethereum -warp +archive    |      6_850_000 |       1.8T | --pruning archive            |

What does OpenEthereum’s command line output mean?

When running OpenEthereum using the command line, a lot of information is displayed in the terminal. Here is a description of these logs.

While syncing the full node

Example: 2018-04-30 16:10:13 Syncing #5532478 9ce2…0499 69.28 blk/s 235.7 tx/s 15 Mgas/s 0+ 17 Qed #5532493 25/25 peers 5 MiB chain 128 MiB db 2 MiB queue 3 MiB sync RPC: 0 conn, 0 req/s, 0 µs

Imported blocks once the node is synced with the top of the chain

Example: 2018-05-02 12:33:23 Imported #3153278 28e4…9981 (12 txs, 3.19 Mgas, 6.84 ms, 12.40 KiB) + another 1 block(s) containing 5 tx(s)

Verifying blocks after warp sync

Example: 2018-05-11T15:25:27.225Z 2018-05-11 15:25:27 UTC #40653 13/25 peers 37 MiB chain 182 MiB db 0 bytes queue 24 MiB sync RPC: 0 conn, 0 req/s, 0 µs

Warp Sync allows the node download a snapshot of the state of the blockchain at a block number close to the top of the chain. It allows the node to get in sync with the top of the chain quickly. Nevertheless, a full node needs to verify every block from the genesis. This process is done in parallel with the sync. This line starting with a block number means that the node is currently processing and verifying an older block.

How to contribute to this wiki documentation?

This Wiki is open source, anybody can contribute! If you spot an error, a typo, or feel like creating or amending some content, feel free to do so. Here is a quick how-to:

  1. Visit repository and click on Fork in the top right-hand corner.
    Fork on github
  2. The Wiki will be cloned in your own repo, you will be redirected to
  3. From here you can edit a page directly by clicking on a file and edit it (click on the pen on the top right-hand corner)
  4. Once you are done editing, describe and commit your changes in your master branch
    Commit to master
  5. You will now be able to submit a Pull Request (PR) to the OpenEthereum Wiki repo.
  6. Click on the Pull Requests and then on the New Pull Request button
    Pull Request
  7. From here, you are able to select what branch of your repo should be merged to what branch on OpenEthereum Wiki repo
    Merge into branch
  8. The default option will propose to merge from your master branch to the OpenEthereum Wiki’s master branch, which is fine.
  9. Double check the modifications you made and click on Create a Pull Request when you are sure
  10. Describe your changes and submit it!

Backup, Restore and Files

Where can I find OpenEthereum’s local files?

On Windows blockchain data is located in C:\Users\You\AppData\Local\OpenEthereum while keys and configuration are kept in C:\Users\You\AppData\Roaming\OpenEthereum

On macOS: /Users/you/Library/Application Support/OpenEthereum

On Linux: /home/you/.local/share/openethereum

How can I backup my accounts and keys? How can I restore my keys?

See Backing-up-&-Restoring.

Can I import my keys from Geth?

They get imported automatically. :)

Can I import accounts not created with OpenEthereum or Geth (e.g., MyEtherWallet)?

Copy your keyfiles into your $HOME/.local/share/openethereum/keys directory. OpenEthereum will import all keys found there.

How do I backup my blockchain?

You can just export it to a file:

openethereum export blocks $HOME/ethereum-chain-backup.rlp

How do I restore my blockchain from a previous backup?

Just use import:

openethereum import $HOME/ethereum-chain-backup.rlp

How to delete the blockchain to initiate full re-sync without deleting wallet info?

openethereum db kill --chain=goerli

Basic Operations, Configuration, and Synchronization

How do I run OpenEthereum?

After installing OpenEthereum, just run openethereum from the command line. See also how do I configure OpenEthereum below

After building OpenEthereum from source:

How do I configure OpenEthereum?

You can configure your OpenEthereum client by passing command-line flags to the executable. For usage instructions, see openethereum --usage and for a list of available flags, see openethereum --help or check out the CLI Options here.

In additoin, OpenEthereum can be configured using a TOML file. To start OpenEthereum with a config file, the file needs to be located in:

To use a custom path run $ openethereum --config path/to/config.toml. Read more on OpenEthereum config file here.

What are the security best practices?

What are the different OpenEthereum synchronization and pruning modes?

Since OpenEthereum v1.2, state-trie pruning is enabled by default (--pruning fast). You can disable it by setting the pruning method to archive which keeps all state trie data:

--pruning METHOD               Configure pruning of the state/storage trie. METHOD
                               may be one of auto, archive, fast:
                               archive - keep all state trie data. No pruning.
                               fast - maintain journal overlay. Fast but 50MB used.
                               auto - use the method most recently synced or
                               default to fast if none synced (default: auto).

To reduce the size of the kept pruning history, you can set the minimum number of recent states with the --pruning-history flag:

--pruning-history NUM          Set a minimum number of recent states to keep when pruning
                               is active. (default: 64).
--pruning-memory MB            The ideal amount of memory in megabytes to use to store
                               recent states. As many states as possible will be kept
                               within this limit, and at least --pruning-history states
                               will always be kept. (default: 32)

By default, 64 states are kept.

What can I do when OpenEthereum has trouble getting in sync?

OpenEthereum is running but seems to remain at the same block for a long time.

  1. Make sure you have the latest version of the client.
  2. Go to and ensure it says “Your time is exact”:

    your time is exact

    If it isn’t, get it synced. Your machine will not automatically do this; my machine is routinely 1-2 seconds out of sync which is enough to disrupt peer discovery.

  3. Make sure your network does not block UDP traffic.
  4. Remove your nodes file ($HOME/.local/share/openethereum/network/nodes.json) while OpenEthereum is not running.
  5. Wait a bit longer.

If the problem persists, please run OpenEthereum with -l sync=trace option for a while and post the output here.

Sync is stuck around block 2,421,000 or 2,675,000!?!

These blocks are quite heavy on the IO and take a long time to import, especially on machines with HDD. Consider using --warp or switching to SSD drive.

How can I run OpenEthereum in Docker?

Docker images for OpenEthereum are available via Docker Hub, i.e.:

docker pull openethereum/openethereum

You can view the Dockerfile here.

Can I run OpenEthereum as a daemon or system service?

The versions installed with the Windows and macOS installers automatically configure and enable a system service.

To manually enable the system service for OpenEthereum installed with Homebrew, run:

sudo launchctl enable openethereum
sudo launchctl start openethereum

To manually enable the system service for OpenEthereum installed on Linux, get the openethereum.service file from GitHub.

sudo wget -O /etc/systemd/system/openethereum.service
sudo chmod +x /etc/systemd/system/openethereum.service
sudo systemctl enable openethereum
sudo systemctl start openethereum

How can I stop a OpenEthereum node cleanly?

If you run OpenEthereum in a terminal, hitting CTRL+C will cleanly exit it. Make sure to wait a couple of seconds.

To stop OpenEthereum started as system service, try to stop it with systemctl (Linux) or launchctl (macOS):

sudo launchctl stop openethereum

Another way is to issue a hang-up (HUP) call for the OpenEthereum client, i.e.:

killall -HUP openethereum

How to launch OpenEthereum using the command line on Windows?

  1. Make sure you close OpenEthereum and that no openethereum process is running (using Ctrl + Alt + Esc)
  2. Navigate in Windows Explorer to the OpenEthereum folder where openethereum.exe is, it should be located in C:\Program Files\OpenEthereum
  3. Highlight the complete folder path in the top pane, type cmd and hit Enter windows pane
  4. This opens a command line window in the OpenEthereum folder, you can launch OpenEthereum with CLI flags

How to launch OpenEthereum using the command line on Mac OSX?

  1. Make sure you close OpenEthereum and that no openethereum process is running. (See here how to kill a process)
  2. Press CMD + Space to open spotlight search
  3. Type terminal and hit return to open Terminal app.
  4. Type or paste /Applications/ in the terminal, you can launch OpenEthereum with CLI flags if needed.

CLI, Mining, and Networks

How do I mine with OpenEthereum?

OpenEthereum supports standard Ethereum JSON-RPC interface for mining (eth_getWork, eth_submitWork methods) and thus compatible with any miner which implements Ethereum Proof-of-Work.

First get a OpenEthereum node up and running (either build yourself or install one of the packages; the Setup guide can help you). Next, you’ll need to install your preferred miner. Read more on Mining.

What are the different consensus engines available for OpenEthereum?

How do I get Ether for the Görli, Rinkeby or Kovan testnets?

None of my JSONRPC requests work, they all fail with no output!?!

As a safeguard against a certain type of attack, OpenEthereum requires you to use a special content type. Just add -H "Content-Type: application/json" to your curl command.

Why do my transactions not get mined?

Your gas price is probably too low. Try increasing the gas price to 20Gwei by appending , gasPrice: 20000000000 into your transaction spec or sendTransaction options.

All my ‘eth_sendTransaction’ calls only return ‘0x00000000…00000000’ as return value!?!

You’re probably trying to send from a locked account. Ensure you use the --unlock (to specify which accounts to unlock) and --password (to pass in the file contain any passwords needed to unlock those accounts) so that the accounts from which you’re sending the transaction are unlocked.

I’ve received an abuse message from my ISP/hosting provider. Something about malicious activity triggered by OpenEthereum.

See Network Configuration for some tips on how to configure OpenEthereum to behave.

Does OpenEthereum support the Swarm and Whisper sub-protocols?



Double-clicking the OpenEthereum icon doesn’t do anything!?!

Probably your node is already running (or another node is running, i.e., Geth) and another instance of OpenEthereum cannot be launched with the same configuration (ports, dapps, web interface, etc.).

How can I make OpenEthereum write logs?

You can control the logging level with -l and define a --log_file location:

  -l --logging LOGGING           Specify the general logging level (error, warn, info, debug or trace).
                                 It can also be set for a specific module. Example: '-l sync=debug, rpc=trace'.
  --log-file FILENAME            Specify a filename into which logging should be
                                 appended. (default: None)

LOGGING accepts the following modules: account_bloom,basicauthority,blockchain,chain,client,cull,dapps,discovery,diskmap,enact,engine,estimate_gas,ethash,evm,executive,ext,externalities,external_tx,fatdb,fetch,finality,hw,hypervisor,import,jdb,jdb.fine,jdb.ops,journaldb,jsontests,les,light_fetch,local_store,migration,miner,mode,network,on_demand,own_tx, perf,pip,pip_provider,poa,pubsub,rcdb,reorg,rpc,rpc-client,secretstore,secretstore_net,shutdown,signer,snapshot,snapshot_io,snapshot_watcher,spec,state,stats,stratum,sync,trace,tx,tx_filter,txpool,txqueue,updater,verification,warp,wasm

Additionally, a logging level can be set per module: info, debug, trace (default if no level is specified for a module)


Note that the info logging level of all modules will always be printed, equivalent to -l info.

See also: How to make OpenEthereum write logs?

Where are the logs when OpenEthereum runs in daemon mode?


openethereum daemon --log-file /path/to/openethereum.log

See also: Where are the OpenEthereum log files in daemon mode?

OpenEthereum uses 100% of disk I/O during sync

OpenEthereum is a disk IO intensive application. By default, your system will allow it to block other programs to access the disk while it’s reading and writing. On Linux, you can use ionice, and newer versions of Windows should allow you to navigate to the process (named “openethereum.exe”) in Task Manager, right click, open the “Process priority” sub-menu and select “Background”. If this menu doesn’t appear, you may need to select “More details” at the bottom of the window. A WikiHow article with a description of this process on Windows 7 can be found here, and the process is much the same for newer versions of Windows.

How can I report an issue with OpenEthereum?

If you have any urgent matters, get in touch with us on Gitter. If you run into issues with OpenEthereum, please consider creating a ticket on Github.

Building, Installing and Testing

Are there any installers available?

You can download the latest versions from the releases page on GitHub.

Where can I find official releases?

You can download the latest versions from the releases page on GitHub. :)

Make sure you check the sha256sum, on your command-line, type


and compare the output with the provided checksum at the releases page on GitHub.


Are builds for ARM devices available (i.e., Raspberry Pi)?

There are builds for ARMhf (ARMv7) and ARM64 on our releases page on GitHub.

In addition, The EthRaspbian project provides Debian-flavored images for the Raspberry Pi which includes OpenEthereum as default client. In addition, the EthArmbian project supports Odroid C2 devices.

How do I install OpenEthereum after building?

How do I update OpenEthereum?

Follow the instructions above to download (or build) and install. The new version will replace the old. Nothing additional is needed.

I’m getting build errors, what can I do?

Make sure you are using the latest stable rust compiler. Update with rustup update when using rustup.

I’m trying to build but get ‘libssl’ errors!?!

Install required packages libssl-dev.

Make sure you have set up your 64-bit variables in the build shell before issuing cargo build:

"C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\bin\amd64\vcvars64.bat"

How can I cross-build OpenEthereum for other platforms (e.g., ARM)?

See the documentation for docker build for ARM.

How can I build and run tests?

First, make sure you have the cross-client consensus tests installed:

git submodule init
git submodule update

Then you just run ./ You can run individual tests with cargo test -p <package-name>.

I just scrolled all the way down here and didn’t find what I’m looking for!?!

Get in touch with us on Discord. If you run into issues with OpenEthereum, please consider creating a ticket on Github