Getting Started

A quick start example for Görli Testnet Nethermind synchronization

🔧 Setting up a Virtual Machine

If you are not launching on your laptop/desktop, then you will probably want to setup a cloud VM. You can find more info about setting up everything with selected cloud providers.

Make sure that you configure firewall properly.

You can check supported operating systems and architectures and hardware requirements.

Downloading Nethermind

You need to download the Nethermind package first. There are currently 2 sources providing Nethermind packages. Check this page to find them out

🔛 Launching Nethermind

  • After launching Nethermind via ./Nethermind.Launcher you need to choose the Node to start first.

Nethermind.Launcher initial options
  • First select Ethereum Node and then select Goerli (light Clique testnet)

Network options
  • Select Fast Sync mode. If you are curious about other modes, click here: sync modes.

Selecting Fast sync option
  • Ensure that JSON RPC is enabled by typing yand pressing enter

  • Press enter to skip setting up Host IP 127.0.0.1 will be set as default

If not running local, you may need to change the Host value to the VM public IP address.

Enabling JSON RPC via Nethermind.Launcher
  • Skip the ethstats registration by typing N and pressing enter.

EthStats configuration skip

👨💻 Explaining Nethermind logs

After the node starts, you will see some initial info about the node and then the sync will start. Görli fast sync uses a fast blocks sync mode initially. The fast blocks sync picks some known pivot block from the past and downloads headers, bodies, and receipts downwards all the way to genesis block. All blocks from 0 to the pivot block are showed as Old Headers in the fast blocks sync logs. The console display shows the number growing from 0 to pivot, but this is just to make the display more user-friendly.

You will see some information about the sync progress, like below:

  1. Shows the number of already downloaded headers, bodies and receipts under the name Downloaded out of all to be downloaded in the fast blocks stage.

  2. Shows the current queue of already downloaded blocks, headers and receipts waiting for being saved to the database.

  3. Shows the current download speed (blocks per second - bps).

  4. Shows the average download speed (blocks per second - bps).

Fast blocks sync logs

When the fast blocks stage finishes, there will be some period of downloading blocks between the pivot and thelatest blocks which will have some additional info:

  1. Shows the last entry from the fast blocks stage.

  2. Shows the mode transition moment.

  3. Displays the speed (in blocks per second) of all headers, bodies and receipts at the same time.

  4. Additional info will appear every 30000 blocks with information about the Görli epoch being stored.

Görli fast sync logs

After the fast sync part finished, the node will transition to the state sync stage when the state trie is being downloaded. Much information is displayed about the progress, as this process may take a long time on mainnet (a few hours).

  1. Total elapsed time in state sync is displayed.

  2. The total percentage of downloaded DB size is displayed (on mainnet the sync finishes around 34GB in March 2020, on Görli around 800MB).

  3. branches stands for the percentage of downloaded branches.

  4. Download speed in kilobytes per second is displayed.

  5. accounts stands for the number of accounts data downloaded already.

  6. nodes stands for the number of Patricia trie nodes downloaded by the sync process.

  7. diagnostic shows the time spent in the DB write / read access. The higher the value, the worse. It may get much worse if you restart the node during the sync process, as we need to recreate some caches then by reading data from the DB.

Görli state sync logs

When the state sync is nearing completion, you may see a series of branch sync information reloading many times from 0% to nearly 100%. This is the node trying to retrieve the few remaining state nodes and progressing with the head block rapidly:

Görli branch sync logs

At some point, the entire state is downloaded and the node enters the full sync mode and will allow you to issue CLI / Web3 queries and send / receive transactions🥳

  1. The root is saved at the moment when the entire Patricia trie is downloaded.

  2. We also clearly state that the node transitions to the full sync.

  3. When you see the block being processed, then you are in the full sync and the newly arrived block is being calculated.

  4. Every two minutes you will see a summary of connected peers with their client version, IP address, highest synced block, and data download speeds.

Görli full sync logs

Now you can launch CLI in the separate process (launching Nethermind.Launcher again and selecting CLI instead of Node). You can read more about CLI here.

You can also connect to the node from Metamask by selecting localhost:8545 from the Metamask network list.

Metamask localhost connection